PSX-A-26 Late-Breaking: The perch competition index of small cage laying hens

A total 72 Lohmann white laying hens at 7 weeks old were used to evaluate the relationship between social order and perch utilization. All laying hens were randomly divided into 12 cages, 6 birds in each cage. The aim of the study is to verify the hypothesis that high-ranked chickens will use perch more when there are only the perch in cage. The study researches the use of perch (including the behavior of the perch) of all hens by setting up the increasing the length of the perch. Using Clutton-Brock index by observing four behaviors (aggression, threat, replace and chase) to determine the social order of the laying hens. The data are analyzed by the generalized linear model (GLMM) in SPSS 23 software. The results showed that the higher rank laying hens used perch more times and time than other subordinate hens (P < 0.001), and the lying, preening and comforting behaviors on the perch increased accordingly (P < 0.001). Except for the highest rank of laying hens, the use of the perch was not significantly different among other subordinate ones (P > 0.05). The conclusion of this study is providing the perch for the caged laying hens can reduce their density on the floor of the cage and make the group stable more quickly. Secondly, higher-ranked hens will use more the perch, and the subordinate hens will reduce the positive conflict with the high-ranked ones. Therefore, providing perch for furnished caged laying hens is beneficial to the welfare of the laying hens in the cage.