Assessment of the effects of separate sex feeding on the welfare and productivity of broiler breeder females.

1. The welfare and productivity of female broiler breeders were studied in pens containing 15 females and 1 male where the sexes were fed together or separately by means of a grid with 40 mm spaces over the female feeders. 2. Average head width did not increase after 25 weeks of age. 3. The rate of lay was lower in separate compared with mixed-sex-fed pens but egg weight was similar. 4. The incidence of swollen heads and beak lesions was higher and feather loss and rate of food intake was lower in separate compared with mixed-sex-fed pens. 5. It was concluded that the grid spaces should be 42 mm wide to avoid adverse effects on welfare and productivity.