Liu, K., Xin, H. 2017. Effects of horizontal distance between perches on perching behaviors of Lohmann Hens. Applied Animal Behaviour Science 194, 54-61.

Perching is a highly-motivated natural behavior of laying hens that has been considered as one of the essential welfare requirements. The objective of the study was to evaluate perching behaviors of laying hens as affected by horizontal distance (HD) between parallel perches. A total of 48 Lohmann white hens in three groups (16 hens/group) were used, 68 weeks of age at the experiment onset. For each group, hens were housed in an enriched wire-mesh floor pen (120cm L×120cm W×120cm H) equipped with two round galvanized tube perches (120cm long×32mm diameter, an average of 15cm perch space/hen). HD was varied sequentially at 60, 40, 30, 25, 20 and 15cm and then in reverse order. A real-time monitoring system was developed to continuously record hen’s perching behaviors. The number or proportion of perching hens, perching duration, and perching trip and frequency were analyzed using an automated VBA (Visual Basic for Applications) program developed in Microsoft Excel. Heading direction of the perching hens and pattern of the perch occupancy were determined manually by video observation. Results showed that reduction of HD to 25cm did not restrain hens’ perching behaviors, whereas HD of 20 or 15cm restrained perching to some extent. Specifically, at HD of 25cm, hens perched interlacing with one another to maximize use of the perches during the dark period. As a result, the proportion of perching hens and perching duration for HD of 25cm were not reduced as compared to HD of 30–60cm. However, the proportion of perching hens was significantly reduced at HD of 15cm (P=0.001–0.025). HD of 15 and 20cm also significantly reduced daily perching time of the hens. In contrast, perching trip or frequency and heading direction of the perching hens were not influenced by HD (15–40cm) except for HD of 60cm. The results suggest that although 30cm is the recommended minimum HD, 25cm may be considered for situations where additonal perches are necessary to meet all hens’ perching needs.