Design and testing of a novel environmental preference chamber

Preference testing is one method for assessing animal perceptions regarding their housing environment and can assist with animal welfare assessment. No literature was found detailing specific designs for the compartments and their temperature and ammonia distribution. A novel system was designed and built as an environmental preference system (EPTS); the system has three parallel connected compartments separated by an automatic door. For the appropriate interpretation of animal responses for environmental testing, it is important to ensure precise control, stability, and uniformity of environmental control. Set-point values of 15, 22, and 30 °C and 0, 20, and 40 ppm_v NH₃ were randomly applied to all compartments during the testing. The system has proven to be capable of providing distinct simultaneous environments in each compartment (t_db of 15.8 ± 1.4 °C, 22.4 ± 1.0 °C, 30.1 ± 0.8 °C and NH₃ concentrations of 3.5 ± 2.8 ppm_v, 19.4 ± 4.1 ppm_v, and 38.2 ± 4.4 ppm_v). The validation of the EPTS was conducted with a group of nine broilers that could transit between the compartments of the EPTS and avoid the heat stress environment. This system can be used for environmental preference studies with animals within the limits reported for the stability, repeatability, and uniformity of the environments.