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The frequency of some behaviours of growing rabbits was studied in pens keeping the animals either on wire net or combined (half of the floor wire net, half of the floor straw litter) floor at different stocking densities. The combined floor could be favourable by increasing the frequency of the social behaviour and decreasing the frequency of the stereotypes, but it decreases the comfort behaviours and the resting time. The decrease of stocking density from 16 to 12 or 8 rabbits/m² significantly increased the stereotypes.

Using the so-called TOBEC (Total Body Electrical Conductivity) method for the in vivo determination of egg composition, the effect of egg composition on the slaughter characteristics of hatched chicks was examined in the ROSS-308 meat-type genotype. Chicks hatched from eggs with low, average and high electrical conductivity were slaughtered at 42 days of age. It was found that the weight of all of the examined traits showed highest values in the case of chicks hatched from eggs with low electrical conductivity, while the lowest values could be observed in the case of chicks hatched from eggs with high electrical conductivity. Similar tendencies were observed also in the case of the ratio of the examined slaughter traits to the slaughter weight, but in this case the differences were not statistically proven (P>0.05).

The effect of egg size and composition on the viability of the offspring has been tested in several former experiments, but the clarification of these correlations was mainly hindered by the lack of a reliable technique/equipment, capable of determining the egg composition in vivo. In the course of the present work electrical conductivity (the so-called TOBEC method) was applied for determining the fat-free mass and the fat content of intact eggs in vivo. Using hen’s eggs in this trial it was established that for predicting the fat-free mass in hen’s eggs, the weight of eggs seems to be a very good predictor (R2=0.99) and therefore the use of the TOBEC method is not necessary in this case. In prediction of the weight and ratio of fat, the common use of the E-value (total conductivity index) and weight of eggs in the regression models resulted in a medium accuracy of prediction (R2=0.48-0.49).

Applicability of computer tomography (CT) was examined for the in vivo determination of egg yolk ratio in commercial hen’s eggs. Altogether 60 eggs were measured by CT, and two different evaluation methods were tested for the prediction of the egg yolk ratio. Because of the overlapping of the X-ray density values of the yolk and albumen, the evaluation based on the X-ray absorption seems not to be useful for the in vivo prediction of the egg yolk ratio. The determination of the surface of the egg yolk on the cross-sectional images resulted in a 69.3-74.1% accuracy of prediction, depending on the number of scans involved in the evaluation.