Form but not frequency of beak use by hens is changed by housing system

In order to verify the hypothesis that hens in different housing systems have the same time budget for different beak-related behaviours, we compared the pecking behaviour of hens in six housing systems: small (SC) and large (LC) conventional cages, small (SF) and large (LF) furnished cages, single-tiered aviary (SA), and free-range (FR). At the age of 16 weeks, 284 medium hybrid layers were randomly divided into six groups and moved to the six housing systems. The number of hens performing behaviours using the beak (grazing, eating, drinking, preening, aggressive pecking, gentle feather pecking, severe feather pecking, litter pecking, and object pecking) was recorded at various ages up to 63 weeks of age. Grazing by a large proportion of hens was observed in FR, and litter pecking by a large proportion of hens in SA. The proportions of hens eating, drinking, and preening were higher in SC, LC, SF, and LF than in SA, and higher in SA than in FR (all P < 0.05). The proportion of hens performing object pecking was higher in SC and LC than in the other systems (all P < 0.05). The proportion of hens performing severe feather pecking was higher in LF and SA than in FR, and more in FR than in SC, LC, and SF (all P < 0.05). The percentages of hens performing all pecking behaviours were almost identical among the six housing systems (63.0 ± 7.1% in SC, 63.0 ± 5.9% in LC, 65.6 ± 5.4% in SF, 64.7 ± 5.0% in LF, 62.9 ± 5.9% in SA, and 64.9 ± 5.6% in FR), indicating that the total frequency of beak use was almost the same regardless of the housing system, although the breakdown of types of beak use was different. We conclude that caged hens may express a motivation for beak-related behaviour by directing it at food, drinking nipples, their own feathers, and the cage wires, although feather pecking appeared not to be decreased simply by the redirected pecking.