PERCH LENGTH IN CAGES FOR MEDIUM HYBRID LAYING HENS

1. ISA Brown hens were housed as groups of 4 from 18 to 72 weeks in 24 cages 450 mm deep, each with a softwood perch of rectangular cross-se ction fitted across the rear. There were 4 treatments, each with 6 cag es: cage widths and perch lengths were 480, 520, 560 or 600 mm. 2. Day time perching did not differ significantly between the treatments. At night, over the whole year, 81% of birds in the 480 mm cages and 86% i n the 520 mm cages roosted on the perch. This figure reached about 95% in the 560 and 600 mm cages, significantly more at most ages than in the 480 mm cages. 3. Feather damage was slightly less, but claw proble ms slightly more, in the 2 wider treatments than in the 2 narrower tre atments. Birds in the wider cages were calmer when approached or handl ed by humans than those in the narrower cages. This may have been asso ciated with variation in space allowance between the treatments. 4. Th ere was a trend for lower production in the 480 mm cages than in the o ther treatments which may have been associated with the reduced feedin g space in this treatment. There were few other treatment differences in production traits. 5. The balance of the evidence from this study i s that when perches are provided in laying cages for medium weight hyb rids, 140 mm of perch space per hen is adequate. For the amelioration of a number of the welfare problems of conventional cages, provision o f perches should be combined with other modifications.