The influence of access to aerial perches on fearfulness, social behaviour and production parameters in free-range laying hens

摘要

The aim of this trial was to determine the influence of aerial perches on welfare and production parameters in free-range laying hens. Five commercial free-range houses, each containing between 7000 and 8000 birds, were used. Each house and range area was split in half to create two treatments. In half of the house the birds had access to aerial perches (P) and in the other half they did not (NP). Perches were provided from the start of the lay cycle at 16 weeks of age, and remained in place until the end of the lay cycle (at approximately 74 weeks). Behavioural observations took place over two day periods at intervals between 17 and 70 weeks of age. During day 1, tests of fearfulness and observations of aggressive and feather pecking behaviours were performed. In addition, twenty birds per replicate were randomly selected and weight, body condition, feather coverage and resistance to handling were measured. The use of the range area by birds was assessed on day 2. The percentage of eggs laid out of nest boxes ('floor eggs') was recorded continuously on three of the farms, and egg quality was assessed from a sample of eggs every 10 weeks across the production cycle on all farms. Access to aerial perches significantly reduced the level of aggression in the slatted and litter areas of the house (P<0.05). P birds had a significantly lower flight distance from the observer than NP birds (P<0.05). In addition, NP birds resisted more to being handled than P birds (P<0.01). P birds were heavier (P<0.01) and had a greater body condition score (P<0.05) than NP birds. There was no effect of treatment on feather coverage (P>0.05), egg quality parameters (all P>0.05), or the proportion of floor eggs (P>0.05). In conclusion, these results suggest that the provision of aerial perches in commercial free-range farms leads to welfare benefits in terms of reduced fearfulness and aggression, and improved body condition.