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Housing environment has become a driving factor on hen health, egg quality and efficient production in intensive poultry industry. In large layer poultry housing system, an environmental index is typically used to control air conditions, including air temperature (T), relative humidity (RH) and concentration of carbon dioxide (CO2) in different season. In hot seasons, thermal environment of laying hen housing is usually assessed using the temperature humidity index (THI) via the online monitored temperature and relative humidity. However, the simple assessment cannot meet the harsh requirement of indoor air quality in a large layer house, as the stocking density increases in recent years. In this paper, a comprehensive environmental index (CEI) was proposed based on the radar map to integrate the impacts of both thermal and air quality factors, in order to systematically assess the environment comfort of the birds. A LabVIEW software system was selected to illustrate the environmental comfort using the fuzzy mathematics. Five key environmental factors, including temperature, RH, air velocity, concentration of CO2 and ammonia (NH3), were used to evaluate the environmental comfort of laying hen housing, where the their weights were normalized in a radar map. In the visualized system, early warning can be delivered when either a single factor or the CEI was over the prescribed value, and thereby a quick action can be taken to adjust the environmental conditions in the layer housing to a comfort level. A field measurement was carried out at a commercial layer breeder farm in Hebei province from January to February, and from July to August, 2019. The experimental results indicated that a good performance of the CEI can be obtained to assess the comprehensive environment in the tested house via monitoring the five environmental indexes. The specific sensors were properly settled in the henhouse. The data of environmental conditions was collected to verify, and then the maximum of five indexes were selected for later use. During the summer daytime, the CEI agreed well with the THI, indicating the positive impacts of thermal environment on the comfort of the birds, while it performed better to integrate the thermal and air quality at night time. In winter, the increase in the weight of CO2 concentration can contribute to the CEI for the comfort in layer housing system. The in situ monitoring data in the actual use demonstrated that the CEI can efficiently represent the change of comprehensive environmental comfort in the chicken house, and respond to the interaction between environmental factors in each period, especially when the air quality has an increasing influence on the comprehensive environmental comfort at night in summer and in winter. The findings can provide a promising method to systematically evaluate the housing environment via the five key factors in laying hen housing, further to improve the birds comfort via precisely controlling the air conditions in intensive poultry production. [ABSTRACT FROM AUTHOR]

Living in a comfortable environment during the period of egg production will enable laying hens to achieve their genetic potential. With the development of the poultry industry to larger scale, the air quality in laying house has become the most important factor affecting the health level and production performance of laying hens. Because of the complexity of environmental factors, such as temperature, relative humidity, wind speed, and concentration of CO2 and NH3, it is difficult to describe the level of the environmental comfort quantitatively. In this study, the real-time system of monitoring environment comfort for laying hens was established by the following methods. Firstly, the comfort thresholds of temperature, relative humidity, wind speed, and concentration of CO2 and NH3 for laying hens were established respectively by investigating relevant references. The results showed that the temperatures for comfortable zone (CZ), less comfortable zone (LCZ) and uncomfortable zone (UZ) were 18-21 ℃, 13-18 or 21-26 ℃, and <5 ℃ or >30 ℃ respectively. As for the RH, the temperatures for these 3 zones were 60%-70%, 40%-60% or 70%-72%, and <40% or >72% respectively. The ranges of wind speed for CZ, LCZ and UZ in winter were 0.1-0.2 m/s, 0-0.1 or 0.2-0.25 m/s and >0.25 m/s respectively, and in summer were 0.5-1.5 m/s, 0.25-0.5 or 1.5-2.5 m/s and <0.25 or >2.5 m/s respectively. And the concentrations of CO2 for these 3 zones were <1 500, 1 500-4 000, and >4 000 mg/m3 respectively; the concentrations of NH3 were <15, 15-20, and >25 mg/m3, respectively. Secondly, the theory of fuzzy comprehensive evaluation was used for data fusion of the environment factors, and AHP (analytic hierarchy process) was applied to determine the weight of the environment factors in winter and summer. The results showed that the weight set of temperature, relative humidity, wind speed, concentration of CO2 and NH3 in winter was 0.428 6, 0.151 1, 0.049 5, 0.282 8, and 0.087 9, respectively, and in summer was 0.432 6, 0.241 8, 0.102 9, 0.081 3, and 0.141 4, respectively. Thirdly, a real-time data collection and analysis system of laying house environment was built through the LabVIEW platform, and the real-time environmental comfort evaluation was presented in this system. Lastly, a new method named comfort time proportion method was developed to collect the statistic data of environmental comfort during feeding period. On the basis of the platform of Agricultural Internet constructed by Key Laboratory of Agriculture Engineering in Structure and Environment, Ministry of Agriculture, the laying houses in the Huangshan Deqingyuan Poultry company and in the Shangzhuang Experimental Station of China Agricultural University were selected as the environmental data acquisition node, and then the real-time monitoring system of environmental comfort for laying hens was tested and verified. Compared with the single environment factor, the system can reflect the environmental comfort of the house more comprehensively. And the environment comfort of the laying house in Deqingyuan was better than that in Shangzhuang Experimental Station in winter. The outcomes of this paper will be helpful for evaluating the environment comfort for laying hens. [ABSTRACT FROM AUTHOR]