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1. We have chosen papers which we feel are representative of important subjects which have been covered by the Journal over a period of 50 years. We would not claim that these are objectively the best papers, for that is a matter of personal judgement, but we consider that they have made significant contributions to knowledge and understanding in poultry behaviour and welfare. 2. John Savory has selected 8 papers from Volumes 1-25 of British Poultry Science (1960-1984), which deal with 5 different aspects of behaviour and welfare: embryonic responses, feather pecking and cannibalism, cage floor preferences, lameness in broilers and myopathy in turkeys. 3. Barry Hughes has selected 11 papers from Volumes 26-50 (1985-2009) of British Poultry Science. Four topics been chosen: broken bones in layers, furnished cages, interaction of birds with machines, and stocking density and bird space.

1. Heart rate, intra-aortic blood pressure, deep body temperature and telencephalic EEG were monitored by radiotelemetry in 6 freely moving immature broiler breeders (three in each of two years), during routine food restriction and then ad libitum feeding, over two 24-h periods in each feeding state.2. Heart rate, blood pressure and body temperature were all higher during ad libitum than restricted feeding, and heart rate and body temperature were higher by day (12 h) than at night (12 h). The decreases in heart rate and body temperature at night were greater during restricted than ad libitum feeding. Blood pressure tended to be higher at night, except in year 2 during restricted feeding. Body temperature and ambient temperature were higher in year 2 than year 1.3. During restricted feeding, marked peaks in heart rate, blood pressure and body temperature in the 15 min after provision of the daily food ration at 09:00 h, when birds were eating, were equivalent to corresponding values seen during ad libitum feeding.4. Relative powers in delta (1 to 4 Hz) and theta (4 to 8 Hz) frequency bands of the EEG power spectrum were higher at night in year 2 only, while power in the alpha (8 to 12 Hz) band was higher at night in both years.5. It is concluded that most of the variation in heart rate, blood pressure and body temperature between feeding states and times of day/night can be accounted for in terms of variation in food intake and energy expenditure. The greater slow wave (delta, theta) EEG activity seen after lights-off in year 2 may reflect non-paradoxical sleep at that time.

Broiler breeder chickens show apparently abnormal behaviours when subjected to routine quantitative food restriction during rearing. By using a combination of videorecording and radiotelemetry, this experiment addressed the question of whether such behaviours are associated with de-arousal. In each of 2 years, 3 female chickens had radiotelemetry devices (Data Sciences) implanted surgically at 12 weeks of age, for measuring putative physiological indices of arousal (heart rate, blood pressure, body temperature, telencephalic EEG). Subsequently, when caged individually and moving freely, they were monitored over 2 days when their daily food ration (60 g pellets provided at 0900 h) was all eaten in <10 min. Their behaviour (nine categories) and arousal indices were recorded in every minute during the photoperiod (0700 to 1900 h), using special computer software for videorecording (Noldus) and radiotelemetry (Dataquest LabPRO) analyses. Most time was spent in behaviour categories stand, push bar and feeder directed. Heart rate, blood pressure, body temperature, and relative powers in delta (1-4 Hz) and theta (4-8 Hz) frequency bands of the EEG power spectrum were all highest during feeder directed, whereas heart rate, temperature and delta EEG were all lowest during stand. Judging from significant correlation coefficients between times spent in different behaviours and corresponding physiological variables, across the day, and between ranked mean values of the 6 birds, other trends were also evident. For example, total time spent in all (non-food directed) oral behaviours was related positively to an index of de-arousal (slow wave EEG) and negatively to an index of arousal (heart rate). Collectively, however, these results provide apparently conflicting evidence of both arousal and de-arousal being associated with every behaviour analysed. This conclusion is explicable if abnormal behaviours are related to arousal in a homeostatic way [Savory, C.J., Kostal, L. Temporal patterning of oral stereotypies in restricted-fed fowls: 1. Investigations with a single daily meal. Int. J. Comp. Psychol. 1996, 9:117-139.], being both stimulated by it and reducing it.

Under Council Directive 1999/74/EC, minimum space allowances per laying hen range from 550 cm(2) in unfurnished cages to 1111 cm(2) in alternative housing, and to 40,000 cm(2) outdoors for free-range hens. In official reports on the welfare of laying hens, there is recognition that knowledge of their space requirements is inadequate. This experiment studied expression of behaviour, including spacing, in five groups of six and one group of five ISA Brown hens aged 21-33 weeks in an adjustable test pen providing 600, 2400, 4800, 7200, 9600, and 12,000 cm(2) floor area per hen. Each group was tested with every treatment. Home pens provided 2400 cm(2) per hen. The main aim was to identify a hypothetical point at which mutual repulsion equals mutual attraction (a 'broken stick' response). Sequencing of treatments was according to a Latin square design, daytime tests lasted 2 h and had no feeder or drinker present, and overnight tests were done with 2400, 7200 and 12,000 cm(2) per hen with a feeder and drinker present. Groups were video-recorded from above to allow repeated measurements of spacing and other behaviours. In daytime tests, the relationship between mean distance to nearest neighbour and floor space allowance was asymptotic, rather than a 'broken stick'. The steepest part of the response was between 600 and 4800 cm(2) per hen. Changes in other behaviours were greatest between 600 and 2400 cm(2), and there was no significant change above 7200 cm(2). Spacing behaviour responses at night were the same as by day. It is concluded that any space allowance of less than about 5000 cm(2) per hen imposes at least some constraint on free expression of behaviour, and that hens would benefit from any increase above the current minimum 1111 cm(2) usable area in alternative housing.

1. Preen oil derived from the preen gland has previously been shown to differ in its composition between birds of different ages, sex and diet. As a part of a larger study on preening behaviour and its components, the relative percentages of fatty acids in preen oil were examined in laying hens that differed in age, beak trimmed status, feather pecking status (pecker and pecked) and method of sampling (either direct from the preen gland or from lipid extracted from feathers). 2. Five experiments are described. Fatty acids extracted from lipid were analysed by gas chromatography (GC). Fatty acid composition was affected by age, by whether or not a bird was feather pecked (but not if it was a feather pecker) and by lipid source. 3. Changes in preen oil composition with age (shown here) may be due to changes in circulating concentrations of hormones. Differences in preen oil composition between feather pecked and non-pecked birds may influence plumage odour and therefore taste, making the plumage of some birds more attractive to pecking than others. 4. The proportions of some fatty acids derived from feathers differed to those extracted from the preen gland. Lipid found on feathers is most likely a combination of that from the preen gland and from sebaceous secretions from the skin.

1. The effects of commercial beak trimming on layer pullet behaviour were investigated, with special reference to preening. 2. One-d-old chicks, 96 in all, were housed in 12 litter floor pens, with 8 birds in each, to 20 weeks of age. Approximately one quarter of the beak was trimmed in all birds in half of the pens (BT) at 8 d of age using a hot blade debeaker. The birds in the other pens remained intact (NBT). 3. There was no significant effect of beak trimming on body weight at any age. At the end of the study, upper mandible lengths were shorter in BT birds. 4. Beak trimming had very little effect on behaviour. NBT birds showed more litter-directed behaviour than did BT birds, and BT birds spent more time in preening directed at the preen gland, and at the back while sitting. 5. Feather damage was minimal and there was no difference in mean feather damage scores between treatments at any age. 6. The young age and small amount of beak removed during beak trimming may be at least partly responsible for the lack of effects of beak treatment on behaviour and plumage condition.

Two experiments examined the responses of 16 individually caged laying hens to the presentation of feathers plucked from dead birds of the same genetic line. In the first experiment, hens known from a previous experiment to be either feather 'peckers' or 'non-peckers' (8 of each) were tested for their propensity to eat feathers in four 10min trials, in which they were offered fresh semiplumes measuring 4-6cm (length), one at a time, in front of their cage. Wide variation between birds was observed in numbers of feathers eaten, pecked, picked-up and manipulated. Fourteen out of 16 birds readily ate presented feathers on one or more occasion and both birds that ate no feathers were non-peckers. Peckers ate, picked-up and manipulated feathers significantly more often than did non-peckers (P<0.05, P<0.01 and P<0.01, respectively). A second experiment investigated the possibility that presence of preen (uropygial) oil might contribute to the attractiveness of feathers to eat. The same group of 16 pecker and non-pecker hens were offered a choice between 20 washed and 20 unwashed semiplumes, presented simultaneously in separate containers, in two 10min trials. Unwashed feathers were eaten, pecked and picked-up in preference to washed feathers by both peckers and non-peckers (P<0.05, P<0.01, and P<0.01, respectively), indicating an attraction towards unwashed feathers, or an avoidance of washed feathers for some reason. Peckers and non-peckers did not differ significantly in their preferences. These results provide evidence of a relationship between feather eating and feather pecking at an individual level. The finding that hens could distinguish between normal feathers and those treated in such a way as to alter their olfactory (but not visual) properties suggests olfactory cues may be of importance in determining the attractiveness of conspecific feathers.

Four groups of 15-19 adult ISA Brown hens were studied in pens to assess the relationship between social status and use of perches and nestboxes. This was to test the hypothesis that subordinate hens use these resources more by day, for avoiding dominants, but that dominants use perches more at night, for roosting. The experiment consisted of a 5-week pre-treatment period, when no perches were present, and a 4-week treatment period, when each group was tested with different perch treatments (No, Low, Medium, High). All groups were observed systematically in each week, when all interactions of three types (aggressive peck, non-aggressive peck, approach/avoidance) in a group were recorded by noting the instigator and recipient (from numbered wing tags) onto a matrix. Proportions of time that each bird spent using perches and nestboxes, by day and at night, were also recorded. The results indicate that social status of individual laying hens is relatively stable across time and can be based reliably on counts of either aggressive pecks or approach/avoidances, but not non-aggressive pecks. Aggressive pecks were the most frequent type of interaction observed, and were reduced by the presence of perches. Use of nestboxes, but not perches, was greater at night than by day. There were weak tendencies for perches, and to a lesser extent nestboxes, to be used more by lower ranking birds by day, but not at night. There was some evidence of increased use of these resources by higher ranking birds at night. It is concluded that provision of perches reduces bird density on the floor (where nearly all interactions occurred), allows subordinates a means of avoiding dominants by day, reduces frequency of agonistic interactions, and should thus benefit laying hen welfare.

1. In recent years, the UK egg industry has become increasingly dependent on plant protein sources, in particular soyabean meal, and it has been suggested that this trend (and/or the concomitant absence of animal protein in layer diets) might be causally related to increased feather pecking and cannibalism. 2. This study examined the development of pecking damage in relation to dietary protein source, by rearing 12 groups of 12 layer pullets to 24 weeks of age on diets based on 'animal' (fishmeal) or 'plant' (soyabean meal) protein. 3. Damaging pecking began at 6 weeks of age, in three groups (one plant and two animal). Injurious pecking began at 18 weeks of age, and affected four groups (two plant and two animal). 4. Greater numbers of vigorous pecks/pulls were observed in plant protein groups throughout the experiment, although they were significantly higher only between 13 to 16 weeks of age. Pecking damage scores did not differ between treatments. 5. Dietary protein source did not affect plasma oestradiol, progesterone or egg production. 6. These results do not support the notion that inclusion of fishmeal in laying hen diets prevents or alleviates feather pecking and cannibalism.

Growing broiler breeder chickens are fed restricted rations to limit body weight at sexual maturity. This experiment tested a proposal (Brouns, F., Edwards, S.A., English, P.R., 1994. Effect of dietary fibre and feeding system on activity and oral behaviour of group housed gilts. Appl. Anim. Behav. Sci. 39, 215-223.) that feeding motivation is reduced by using qualitative rather than quantitative food restriction, and it examined relationships among suppression of growth rate, feeding motivational state and general activity level. From 2 to 15 weeks of age, female broiler breeders were reared in six groups of 20, each with a different feeding treatment. The six treatments were: high and low levels of diet dilution (600-700 g/kg and 300-350 g/kg oat feed, ad libitum), appetite suppression (50-60 g/kg and 25-30 g/kg calcium propionate, ad libitum) and quantitative restriction (recommended daily ration and twice that amount). Birds were conditioned to an operant (PR1 schedule) feeding procedure with their respective treatment diets from 3 to 7 weeks, and this was used to measure feeding motivation in 12-min tests at three times of day (1000, 1300 and 1600 h) at 8, 10, 12 and 14 weeks. Proportions of time spent sitting were measured as an index of general inactivity in systematic observations at 9, 11, 13 and 15 weeks. Although the diet dilution and appetite suppression (qualitative) treatments did not limit growth rates as intended, they and the quantitative treatments produced a range of mean body weights to compare with feeding motivation whenever birds were tested. With body weight as a covariate, there were significant effects on numbers of operant responses in 12 min (the measure of feeding motivation) of weight, age, time of day and treatmentxtime interaction, but not treatment. Feeding motivation was positively correlated with suppression of growth rate, regardless of how that suppression was achieved. However, the experimental procedure required all test birds to be without food from 0900 or 0915 h, and motivation was lowest in the earliest (1000 h) test with qualitative but not quantitative treatments. Hence, there was some evidence that feeding motivation may be partially suppressed with qualitative food restriction; distinction can be made between short-term and longer-term feeding motivation. General activity level (inversely reflected by time spent sitting) was closely correlated positively with both suppression of growth rate and feeding motivation. As a fundamental relationship between feeding motivation and reduction of growth rate was not altered by using qualitative rather than quantitative food restriction, these results support an earlier conclusion (Savory, C.J., Hocking, P.M., Mann, J.S., Maxwell, M.H., 1996. Is broiler breeder welfare improved by using qualitative rather than quantitative food restriction to limit growth rate? Anim. Welfare 5, 105-127.) that broiler breeder welfare is not improved with qualitative restriction methods.

1. As part of a programme investigating the causation of pecking damage in fowls, this experiment tested a proposal that birds may receive more feather pecks when their plumage colour contrasts with floor litter colour, because litter particles on plumage (as a consequence of dustbathing) may then have greater stimulus value. 2. Groups consisting of 7 light- and 7 dark-coloured bantams were reared from 1 to 11 weeks of age in pens with either wood shavings (light coloured, n=6) or peat (dark coloured, n=6) floor litter. 3. Feather loss from pecking commenced in the 3rd week of life and increased thereafter, but observed pecking damage scores were not consistent with the hypothesis being tested. 4. Despite many more pecks at birds being seen (over 10 weeks) in the wood shavings groups' (661 at particles on plumage, 1795 not at particles) than in peat groups (205, 787), there was no effect of litter substrate on pecking damage. The only evidence supporting the proposal was the finding that, in groups on wood shavings, significantly more pecks at particles on plumage were directed from light coloured birds towards dark ones, than from light to light, dark to light, or dark to dark. 5. Feather eating was confirmed from the presence of feather material in 2% to 15% of faecal droppings collected from each group at 11 weeks, but these proportions were not correlated with pecking damage scores. 6. The results imply that only some feather pecks/pulls were damaging and only some eaten feathers were pulled from other birds.

1. This paper reports 4 experiments with groups of 10 to 20 growing bantams in multi-unit brooders, which investigated effects of certain environmental and dietary factors on development of feather pecking damage to 6 weeks of age. Damage was assessed according to a subjective scoring system. 2. A test of food form (pellets, mash, mash diluted with 100 g/kg powdered cellulose) confirmed that pecking damage tends to be greater with pellets than with mash but there was no significant difference between the low damage scores associated with undiluted and diluted mash treatments. 3. A test of group size (10, 20 birds) and stocking density (744, 372, 186 cm2/bird) showed that variation in pecking damage was associated with group size x density interactions. 4. A test of dietary supplementation with L-tryptophan (0, 10, 20 g/kg) showed suppression of pecking damage with the higher (20 g/kg) dose, compared with the control (0 g/kg) treatment. 5. A test of dietary protein source (plant, mainly animal, mainly semipurified) showed no difference in pecking damage scores between treatments.

1. This study investigated relationships between the timing of stress, duration of oviposition delays and consequences for eggshell quality, in 2 experiments with ISA Brown hens. 2. Periods of up to 6 h of environmental stress (relocation from an individual cage to a larger one containing 3 unfamiliar hens), commencing up to 4.5 h before predicted oviposition time, reliably induced oviposition delays. Many hens still retained their egg when stress ended. 3. Ovipositions that occurred during stress were never delayed for more than 3.0 h beyond the expected time. Ovipositions that occurred after the period of stress ended usually did so after <1 h if the delay at the end of stress was less than about 2.4 h. Delays that ended either during stress or <2 h after stress ended were classified as short-term. 4. If an oviposition delay was more than about 2.4 h when stress ended, the egg concerned was usually laid much later, after a delay of 7 to 15 h. Delays that ended >5 h after stress ended were classified as long-term. 5. Eggs delayed long-term were white-banded and the subsequent egg was slab-sided, or occasionally soft-shelled. Short-term delays often caused eggshell dusting with varying amounts of superficial calcification. Hence, duration of oviposition delay affects both the number of abnormal eggshells and the degree of abnormality. 6. The present findings are of potential importance to both the egg industry and breeders, because abnormal eggshells cause downgrading and can impair embryonic development. Also, numbers of abnormal eggshells and degree of abnormality can be used as indicators of environmental stress.

To investigate further a putative role of dopamine in control of food restriction-induced behavioural stereotypies, chickens were fed during rearing on either a daily restricted ration recommended by a breeding company, twice the recommended restricted ration, or ad libitum food. They were killed at 60 days of age and their excised brains were dissected into six regions and homogenized. Densities of dopamine D1 and D2 receptors were assessed, after first estimating binding parameters for [3H]SCH 23390 (D1) and [3H]spiperone (D2) in chicken brain homogenates. Specific binding of both ligands was highest in basal telencephalon. Concentrations of dopamine and its metabolites 3,4-dihydroxyphenylacetic acid and homovanillic acid were also highest in basal telencephalon, whereas noradrenaline and adrenaline levels were highest in diencephalon. Dopamine concentration in basal telencephalon and noradrenaline concentration in diencephalon were increased significantly in response to food restriction, but no effect of feeding treatment was found in dopamine turnover, adrenaline levels, or D1 and D2 receptor densities in any brain region studied. The observed changes in brain catecholamine levels are consistent with roles for dopaminergic and adrenergic mechanisms in the control of food restriction-induced behavioural stereotypies in chickens.

Growing parent stock (breeders) of meat-type chickens (broilers), subjected routinely to chronic food restriction, show increased pacing before a single daily meal and increased drinking and pecking at non-food objects (oral stereotypies) afterwards. Expression of these activities is correlated positively with the level of restriction imposed, and is thought to be controlled mainly by central dopaminergic mechanisms. There is published evidence that glucocorticoids can amplify dopamine mediated behaviours, and this paper describes four experiments examining the relationship between corticosterone and behaviour in individually caged broiler breeders. In Experiment 1 (with 3 levels of food restriction), plasma corticosterone concentration was correlated positively with the level of restriction imposed when blood samples were taken in the morning, but not when they were taken in the afternoon. This may be because corticosterone level declines from morning to afternoon with mild but not severe restriction. In Experiment 2 (severe restriction only), plasma corticosterone level did not change significantly with time of day, and mean values of individual birds were not correlated with their observed times spent in oral stereotypies. In Experiment 3 (severe restriction), object pecking increased in a dose-related way after systemic injection of 1-4 mg/kg corticosterone (significant) and 7.5-30 IU/kg ACTH (not significant), and 10-40 mg/kg metyrapone (corticosterone synthesis inhibitor) had no effect. In Experiment 4 (severe restriction), 180 mg/day metyrapone administered in food for 5 days reduced the plasma corticosterone response to injection of 15 IU/kg ACTH on the fourth day, but otherwise had no effect. Significant increases in drinker directed activity after injection of ACTH on the fourth day and 4 mg/kg corticosterone on the fifth day coincided with greatly elevated plasma levels of corticosterone. It is concluded that the oral stereotypies of restricted-fed broiler breeders do respond to induced increases in plasma corticosterone concentration that are supra-physiological, but there may be only a weak association between behaviour and corticosterone within the physiological range.

This paper reports the first successful chronic monitoring (for 30 days) of blood pressure, heart rate, EEG, and physical activity in a freely moving bird, following (described) implantation of a commercially available (Data Sciences International) radiotelemetry device in a 1.6-kg broiler chicken. The tip of the device's pressure sensing catheter was introduced into the descending aorta via a leg (ischiadic) artery and, although the catheter was tied in place, circulation in the leg was maintained and leg function was not impaired. EEG was recorded from the device's paired sensing electrodes positioned on the surface of the telencephalon. Physiological and activity data collected by the radiotelemetry system over 2 complete 24-h periods, 1 and 4 weeks after implantation of the device, were analyzed with the system's own (Dataquest LabPRO) analysis software. The results presented are discussed mainly in terms of variation between light and dark periods.

1. This study investigated effects of plastic anti-pecking devices on food intake and behaviour to assess their applicability in commercial layer flocks. 2. In experiment 1, 72 individually caged ISA Brown pullets were fitted at 16 weeks of age (point of lay) with either 'ring' or 'bumper' beak devices or no device (control), half being fed on pellets and half on mash. The devices were held in place by lugs inserted in the nares. 3. There was evidence of discomfort immediately after fitting the devices, but not thereafter. In the first week, the devices reduced food intake, and were removed from 7 (15%) birds that lost weight consistently. Between 16 and 21 weeks, however, there were no significant effects of beak treatment or food form on either total food intake or egg production with the 65 remaining birds. 4. Beak treatment did not affect feeding efficiency (food intake per minute of feeding). The only behaviour affected was pecking at birds in adjacent cages, which was reduced with the ring device. 5. At 21 weeks, the birds were placed together in groups of 4 to 6 in 12 pens, each group consisting of birds from one of the 6 original treatments, and their behaviour was observed in experiment 2 between 21 and 23 weeks. 6. The only effects of beak treatment on behaviour were that pecking at pen walls was increased with the ring device, while pulling and eating feathers from group mates was seen mainly with control birds fed on pellets. Two birds were cannibalised in a control group on pellets. 7. Devices came off 3 (7%) birds in experiment 1 and were replaced, and rings slipped over lower mandibles of 2 (5%) birds in experiment 2 and were corrected. 8. At 23 weeks, beak lengths were increased with ring and bumper treatments, and pecking damage scores were low with all treatments. 9. It is concluded that these devices are not applicable commercially, but further trials would be justified with new improved designs.

1. Behavioural development in groups of 8 pullets kept in pens with litter floors, and fed on either mash or pellets, was studied from 0 to 10 weeks in a White Leghorn x broiler (F2) hybrid line (experiment 1) and from 0 to 24 weeks in Hisex, White Leghorn and Brown Leghorn strains (experiment 2). The aim was to identify precursors of feather pecking and cannibalism. 2. Rates of body weight gain were consistently greater with pellets than with mash in both experiments. In experiment 2, the onset of lay was at 17 weeks of age in Hisex, 21 weeks in White Leghorns and 23 weeks in Brown Leghorns. 3. Persistent feather pecking, which was not seen in experiment 1, developed in 2 of 12 groups (one Hisex and one White Leghorn, both fed on pellets) in experiment 2, and was studied in detail at 23 and 24 weeks. The more damaging pecking in the Hisex group was followed by cannibalism in the same group. 4. Based on the (often inconsistent) effects of genetic strain, age and food form on behaviour that were observed, a working hypothesis was constructed to account for the aetiology of feather pecking and cannibalism in situations where there is floor litter. 5. An age-related decline in one or more foraging activities may coincide with increases in preening and non-damaging pecking at other birds. Consumption of litter particles and moulted feathers may be reinforcing. Dustbathing may enhance the stimulus value of litter particles when they are contrasted against background plumage colour. This may direct pecking towards the backs of birds, where feathers as well as litter particles may be removed and eaten. Regular pecking and feather removal may lead eventually, after the onset of lay, to vent pecking and cannibalism. This sequence of events may be more likely in groups where activity levels are high.

Quantitative receptor autoradiography was used to measure differences in [3H]DAGO binding to mu-opioid receptors in selected fore- and midbrain regions of chickens subject to varying degrees of chronic food restriction: either R (a recommended restricted ration), 2R (twice recommended restricted ration) or AL (ad libitum). A significant increase in binding of 75% was observed in the paleostriatum primitivum (a homologue of the mammalian globus pallidus) with the R treatment compared to the 2R and AL treatments. This finding concurs with results of earlier pharmacological manipulations with opioid antagonists, which indicated that activation of mu-opioid receptors plays a contributory role in reinforcement of post-feeding oral stereotypies in chickens subject to the same R treatment.

Effects on environmentally induced oral stereotypes (object pecking and drinker directed activity) of antagonists and agonists of dopamine and opioid receptor subtypes were examined in individually caged broiler breeder fowls subjected to chronic food restriction. Three drugs in each category were injected intravenously at three doses, and their effects compared with those of a saline control treatment. With dopamine antagonists, inhibition of both stereotypes was most marked with haloperidol (D2), intermediate with clozapine (D4), and lowest with SCH 23390 (D1). Increased sitting with the high doses of these three drugs may reflect sedation. With dopamine agonists, SKF 38393 (D1) suppressed both stereotypes slightly, quinpirole (D3) did so consistently and potently, possibly reflecting preferential presynaptic action, while bromocriptine (D2) inhibited drinker-directed activity consistently, but its initial suppression of object pecking changed to delayed stimulation with the high dose. This biphasic effect of bromocriptine may reflect change from pre- to postsynaptic action. Two of the opioid antagonists, naltrexone (mu) and MR 2266 (kappa, but also mu), inhibited object pecking partially, while naltrindole (delta) and the opioid agonists fentanyl (mu), BUBU (delta), and PD 117302 (kappa) had delayed and minor effects. These results suggest that expression of object pecking, but not necessarily drinker-directed activity, depends more on activation of D2 dopamine receptors than D1 receptors, the role of D3 and D4 receptors is less clear, and activation of mu and possibly kappa opioid receptors may play a contributory role.

1. From 2 to 21 weeks of age, 150 female broiler-breeder chicks received one of three dietary treatments. Fifty received an ad libitum supply of food (treatment AL). The remaining 100 were given weighed (restricted) rations once a day, 50 receiving the amount per bird recommended in the Ross 1 Parent Stock Management Manual (treatment R) and the other 50 receiving twice this recommended amount (treatment 2R). Water was provided ad libitum for all treatment groups. 2. The daily allowance for R birds increased from 26 g per bird at 2 weeks of age to 94 g at 21 weeks. The intake of AL birds meanwhile increased from 65 g at 2 weeks to 240 g at 19 weeks, before decreasing to about 200 g at 21 weeks. 3. Median heat productions (H) per bird in the R and 2R treatment groups were, respectively, 65 and 40% lower than in the AL when adjustment was made for the reduced food intake of AL birds in the calorimeter chambers. The effects of dietary treatment on fasting H were proportionally similar. 4. Because the increasing divergence in body weights would have made a large contribution to differences in H per bird, the results were adjusted to the median weight of 2.03 kg and to unit weight (1.00 kg). Adjusted fasting heat production was 18 and 11% less in 2R and R birds than in those fed ad libitum.(ABSTRACT TRUNCATED AT 250 WORDS)

Six groups of 25 growing female broiler breeder chickens in pens were fed either on a commercial restricted ration (R), twice that amount (2R), or ad libitum (AL). R and 2R birds were fed daily at 09.00 h and ate all their food in < 15 min. Behaviour was observed systematically at three times of day (once before and twice after feeding time) at 6,9,12, 15 and 18 weeks of age. In general, restricted-fed (R and 2R) birds were much more active than AL birds. There were significant (P < 0.05) effects of feeding treatment on all activities recorded except preening and pecking at the empty feeder (R and 2R birds only); age affected drinking, preening, walking, standing and sitting; and time of day affected all activities except feeding (AL birds only). Activities that appeared to reflect feeding motivational state closest were walking before feeding time, and drinking, pecking floor litter and sitting after feeding time. AL birds (only) panted for about a third of the time at moderate ambient temperatures, and changes in their behaviour with age were thermoregulatory. It is proposed that activities of restricted-fed animals that are dominant after feeding time may be substitutable and have common causation and consequences. Distinction between stereotyped and non-stereotyped behaviour in this context may therefore be misleading., (Copyright © 1993. Published by Elsevier B.V.)

To test a possible influence of dietary fibre on intestinal sugar uptake, rates of absorption of 10 mM-D-[U-14C] glucose and 10 mM-D-[U-14C] xylose were measured in either jejunum or (distal) caecum, by in vivo lumen perfusion, in immature female fowls preconditioned to a standard diet containing (g/kg) either 0, 100, 200 or 400 added dried grass, 200 powdered cellulose, or 200 grass with a polysaccharidase enzyme supplement. When birds were killed after perfusion, dimensions of (unperfused) parts of their alimentary tracts were determined, and recoveries of 14C radioactivity in some body tissues were compared with measured activities absorbed. On average, absorption of glucose was 1.9 and 1.2 times faster than xylose in jejunum and caecum respectively, although these differences varied with dietary treatment and order of perfusion. Increasing grass in the diet caused significant changes in xylose absorption rate in both jejunum and caecum, but only when it was perfused before glucose. With any one sugar and intestinal segment, mean rates of absorption were correlated positively with corresponding mean rates of fluid loss from perfusate. Although their influence on sugar absorption was not well defined, the dietary fibre treatments had more pronounced effects on gross dimensions of parts of the alimentary tract and, hence, potentially on total rates of absorption. Compared with the basal diet, addition of 100, 200 or 400 g grass/kg or 200 g cellulose/kg caused significant increases in small intestine length while 200 g grass/kg with supplementary enzyme did not, and combined caecal length increased with the 400 g grass/kg and the supplementary enzyme treatments. Absorbed 14C activity was recovered in plasma after jejunal perfusions but not caecal ones, whereas it was recovered in liver and in the flushed perfused segment after both types of perfusion. Since there was overlap in absorption rates between jejunum and caecum, this result suggests that the liver may be able to distinguish and treat differently compounds absorbed in the two regions.

A major benefit of supplementing non-ruminant feedstuffs with exogenous enzymes is presumed to be the degradation of plant cell-wall polysaccharides to metabolizable monosaccharide residues. In the present study, metabolic fates of (U-14C-labelled, 10 mM) glucose, galactose, mannose, xylose and arabinose were compared in the fowl, by measuring recoveries of 14C radioactivity in exhaled carbon dioxide excreta and body tissues after administration either by wing vein (iv) or into the crop (ic). A further comparison was made with a tube-fed, enzyme-treated, U-14C-labelled cell-wall substrate, Festuca arundinacea, and a final experiment tested possible competition for absorption between different cell-wall residues. Delays between iv and ic treatments in recovery of 14C in CO2, which were assumed to reflect intestinal absorption, indicated that xylose was absorbed more slowly than glucose and galactose, but faster than mannose and arabinose. Total recoveries of 14C in CO2 and excreta over the whole test period indicated that metabolizabilities were highest with glucose, galactose and mannose, and lowest with arabinose. After testing, 14C recovery in caecal contents was highest with ic arabinose, and recoveries in body tissues, with all sugar treatments, were in the order liver greater than breast and leg muscle greater than abdominal fat greater than plasma. Results with the Festuca substrate showed similar patterns of recovery in body tissues and confirmed an increase in metabolizability with addition of enzyme. The timing of the 14CO2 response with Festuca and a wet enzyme pretreatment was broadly similar to a 'predicted Festuca' response, based on the composition of the substrate and the measured responses with individual (ic) monosaccharides. There was no evidence of any competition for absorption or metabolism among cell-wall residues. It was concluded that glucose release from cellulose is potentially the most important product of cell-wall degradation to contribute to enzyme enhancement of metabolizable energy.

An experimental model is described that was used for assessing in vivo effects in fowls of exogenous enzyme supplementation on the degradation of plant cell walls to metabolizable monosaccharide residues. It was based on tube-feeding U-14C-labelled cell-wall substrates, cellulose, spinach (Spinacia oleracea) or Festuca, with and without enzyme treatments, and monitoring recovery of 14C radioactivity in exhaled carbon dioxide and excreta in the following 8 h. Normal digestion of cell-wall polysaccharides by endogenous microbial activity was also studied by pretreating birds with an antibiotic mixture intended to deplete their intestinal microflora. The results of this pretreatment appeared to confirm the existence of microbial degradation of cellulose in (conditioned) fowls. Judging from differences in 14CO2 production, effects of exogenous enzyme additions were greatly enhanced with all substrates by combining them with a wet pretreatment, thereby increasing the time-period available for them to act in aqueous conditions. However, estimations of digestibilities of cellulose, hemicellulose and pectin with dry and wet treatments, based on recovery of 14C in excreta, indicated that it was only cellulose digestion that was improved by the wet pretreatment. This suggests that degradation of cellulose, which appeared to be slowest, was limited by the dry treatments, whereas that of hemicellulose and pectin was not. Respective digestibilities of these three cell-wall components, from all treatments combined, were in the proportions 1:1.5:4.2.

1. Immature hens were preconditioned to a standard diet containing either 0, 100, 200 or 400 g/kg of added dried grass, 200 g/kg powdered cellulose, or 200 g/kg grass with an enzyme supplement, and were killed at either 10.30, 12.30 or 15.30 hr (after measurement of intestinal sugar absorption reported elsewhere). 2. Contents of caeca removed from these birds immediately after death were weighed and analysed for pH, uric acid, free sugars and volatile fatty acids, and the results related to dietary fibre level and time of day (of death). 3. Wet weights and uric acid concentrations of caecal contents both increased with increasing grass in the diet; neither measure varied with time, thus supporting the proposal that filling of caeca is continuous. Values of pH were all close to neutrality. 4. Mean molar concentrations of glucose, galactose, mannose, xylose, arabinose, fucose and rhamnose were in the proportions 36:2:3:1:4:1:1, respectively. Xylose and rhamnose declined with increasing grass; as did glucose, galactose and mannose with added cellulose; glucose, mannose and arabinose levels changed with time. The relative abundance of glucose in caecal contents should be taken into account when estimating contributions of fermentation products to energy balance. 5. Mean concentrations of acetate, propionate, butyrate, iso-butyrate, valerate and iso-valerate were in the proportions 72:22:16:1:2:2. Acetate declined and iso-valerate increased with increasing grass; the cellulose and enzyme treatments caused increases in acetate and valerate respectively; butyrate, iso-butyrate and iso-valerate levels changed with time.

1. Rates of absorption of two hexose (D-glucose and D-galactose) and two pentose (D-xylose and D-arabinose) sugars were measured by in vivo perfusion, in jejunum, ileum and (distal) caecum, in immature hens conditioned to either a standard (ST) or "high fibre" (ST + 20% grass) diet. 2. Each bird was tested in one intestinal segment with all four (U-14C-labelled, 10 mM) sugars, with either the hexoses preceding the pentoses or vice versa. 3. With all treatments, absorption rates of the hexoses were alike, as were those of the pentoses. Hexose absorption was twice as fast as pentose absorption in jejunum and ileum with both dietary pretreatments, whereas in caecum hexose and pentose rates were similarly high, except when pentose (and its associated fluid transfer) was apparently inhibited by prior hexose absorption with the ST diet. 4. With the ST diet, hexose absorption (per unit length and dry weight) was faster in caecum than in jejunum and ileum, and pentose absorption was also fastest in caecum when all pentose data from testing after hexose were excluded. 5. With the ST/grass diet, hexose absorption was faster in jejunum than in ileum and caecum when expressed per unit length, and pentose absorption was fastest in caecum on a dry weight basis. 6. Hexose absorption was faster in jejunum and slower in caecum with the ST/grass pretreatment than with ST. However, the dietary comparison was not conclusive because it involved birds form (two) different hatches (of similar age and weight) tested at different times.

1. The daily food intake of captive red grouse was measured throughout the year. It was positively related to body weight and to daylength, and negatively to air temperature. Grouse ate more during their main summer moult, and the hens ate most while producing eggs. 2. The total weight of eggs laid was positively related to daily food intake during the 5 weeks before laying, but not to daily intake during laying. The rate at which eggs were laid was related to daily intake during laying as well as before laying. The possible significance of these results for poultry management is discussed.

This paper describes a series of experiments with domestic fowls designed to investigate different effects of peripherally administered bombesin (BBS) and cholecystokinin octapeptide (CCK8), with a view to gaining a better understanding of their proposed roles as physiological satiety signals. Following intravenous injections of 1-10 micrograms/kg BBS or CCK8, short periods of complete inhibition of feeding coincided with periods of abnormal gizzard motility, and longer periods of reduced feeding were associated with periods of abnormal gastrointestinal (GI) motility. Increases in heart rate, measured in a separate experiment, coincided with the periods of altered GI and feeding activities. Effects of the peptides on GI motility and feeding were strongly related to dose with CCK8, but not with BBS, and effects of (2 micrograms/kg) BBS and CCK8 on feeding were additive. Evidence from conditioned avoidance tests suggested that consequences of (10 micrograms/kg) BBS and CCK8 injections may be mildly aversive, perhaps more so with BBS, and in another experiment inhibition of feeding by (8 micrograms/kg) BBS (but not CCK8) was almost abolished in birds tranquillised with a reserpine derivative drug. CCK8 was more potent than BBS at suppressing feeding only when relatively high doses (8 and 10 micrograms/kg) were injected. It is suggested that peripherally administered BBS and CCK8 may act on feeding in similar ways, with animals being distracted by possible abdominal discomfort associated with the abnormal GI responses. The results indicate that immediate discomfort may be more severe with BBS, but that discomfort associated with CCK8 may last longer. It is further suggested that satiating properties of the peptides are less apparent in situations where animals are less easily distracted by discomfort, when their arousal is reduced, when their perception of discomfort is reduced and when their motivation to feed is increased.

There was an increase in the length of the small intestine, caeca and colon when Japanese quail (Coturnix coturnix japonica)were fed on a diet diluted with fibre. No differences were found in the length of the villi and the thicknesses of the submucosal layers throught the large and most of the small intestine between birds fed on the normal diet compared with those fed on the diluted diet. The birds fed on the normal diet appeared to have more mucous goblet cells and lymph nodes in the caeca than those fed on the diluted diet.

This paper presents new information about inhibitory effects of intravenous injections of cholecystokinin-octapeptide (CCK-8) on feeding activity in birds, with particular reference to variation in motivational state. With increasing food deprivation (0, 1, 2 or 3 h) before injection, doses of 2 and 8 micrograms/kg CCK-8 became progressively less effective in suppressing feeding of domestic fowls. As with mammals, latency to feed was shorter, and subsequent feeding activity greater, with deprived than with undeprived birds. Fowls of broiler (meat-type) and layer strains, which have different absolute food requirements but similar relative (per kg body weight) requirements, did not differ in their feeding responses to injections of 1, 8 and 16 micrograms/kg CCK-8. Food intake of fowls fed on a diet diluted with 40% powdered cellulose was suppressed less by the same three doses of CCK-8 than that of birds fed on undiluted food. This may have been because birds with the more bulky diluted food had to spend a greater proportion of time feeding. Broiler chicks aged 2 and 6 weeks, which may have different blood-brain resistance to circulating CCK and which have different relative food requirements, did not differ in their feeding responses to injections of 2 and 8 micrograms/kg CCK-8. These results do not satisfy one of the criteria proposed for demonstrating the action of a satiety agent, that feeding should be suppressed in a consistent manner regardless of motivational state. An alternative explanation for the apparent satiating properties of CCK-8 is suggested, based on similarities in their time-course, and dependence on deprivation level, to abnormal gastrointestinal responses with similar doses of the peptide.

The relationship between gastrointestinal (GI) motility and spontaneous feeding activity was investigated in five immature domestic hens, by recording simultaneously their feeding and contraction of the gizzard and duodenum. Different parameters of GI motility were interrelated, and gizzard contraction frequency (GCF) was used as an overall index of motility. Significant (P less than 0.05) changes in GCF relative to mealtimes varied between individual birds and between different meal length classes. The most consistent change was a rapid increase in GCF at the start of meals, followed by a decline which usually commenced before the end of long meals, but after the end of shorter ones. The increase in GCF commenced before the start of meals in one bird which had longer inter-meal intervals than the rest. There were no consistent changes in GCF at the ends of intervals or meals that might suggest a causal association between motility and hunger and satiety. It is suggested that the observed variation in GI motility may be accounted for mainly by variation in extrinsic stimulation from the vagus nerve.