Effects of cage height and stocking density on the frequency of comfort behaviours performed by laying hens housed in furnished cages

摘要

Spatial restriction and low cage height can reduce the rate at which comfort activities, such as wing flops, stretching, body shakes and tail wags, are carried out by laying hens in conventional wire cages. In this study we investigated the performance of these activities in laying hens housed in furnished cages with perches and nest boxes, similar to those required in EU legislation from 2012. We compared the behaviour of groups of eight hens at a stocking density of 762 cm(2) per bird with that of pairs of hens housed at a lower stocking density of 3048 cm(2) per bird at two'minimum cage heights of 38 cm and 45 cm. The rates of wing/leg stretches (0.80 stretches per hen per hour), tail wagging (0. 76), body shaking (0.48), wing raising (0. 19) and feather raising (0.05) were low, whilst full wing flops were not observed during the study. Hourly rates of performance of wing/leg stretches (0.45 vs 1.06) and tail wags (0.34 vs 1.25) were significantly lower in eight-bird cages than in two-bird cages. We conclude that reducing the number of hens in furnished cages increases opportunities to perform certain comfort activities, but that, even at low stocking densities, comfort activities are rarely observed.