The Edinburgh Modified Cage: Effects of group size and space allowance on brown laying hens

Modified laying cages are being developed in a number of European countries in response to public and legal pressure for improvement of laying hen welfare. The Edinburgh Modified Cage (which has a perch,nest box, and dust bath) is one design which is practical for commercial production. The trial reported here was concerned with specifications including group size and space allowance. There were no major management problems during the year except for an outbreak of red mite which was successfully treated, and egg production was above breeders' standards (with few downgraded eggs), Hens used the space and facilities well. For example, they showed settled nesting behavior and laid 94% of eggs in nest boxes. Their physical condition was also improved in several respects compared to control birds in conventional cages. A group size of five or fewer proved most suitable, with a space allowance of about 675 cm(2)/bird in the main part of the cage (915 cm(2) including the nest box) for brown birds. Egg production will cost more in modified cages than in conventional cages, but less than free range.