[Effects of stocking density on the behaviour and bodily state of broilers fattened with a target liveweight of 2 kg].

The current investigation is a contribution to the animal welfare debate on acceptable stocking densities in broiler chickens. Two stocking densities on similar levels as currently legally regulated (35 kg/m2 und 40 kg/m2) and two cleary lower stocking densities (18 kg/m2 und 25 kg/m2) were investigated in groups of 18 to 42 Lohmann broiler chickens (B) in three batches with each time one replication of all stocking densities. Target weight of the broiler chickens was 2 kg at 39 or 40 days of age. Mortality, final live weights and activity levels were not significantly different between stocking densities. The proportion of time birds were sitting/lying increased in general with age from about 56% to 82%, probably due to their rapid growth. Nevertheless, at the lower stocking densities there was only in single cases. Moreover, significantly more footpads showed medium grade alterations under higher density conditions; high grade alterations were also different between 35 kg/m2 and 40 kg/m2. Walking ability was only different between the lowest and the two higher densities. Altogether results reflect behavioural restriction at the higher stocking densities with increased risks for footpad alterations and lameness. In order to reach clear animal welfare improvements, e. g. in the framework of animal welfare labeling, a considerable lowering of the stocking density is consequently one important measure. However, this recommendation should be further validated under commercial conditions.