Effect of feed restriction on growth, body composition, and egg production of broiler females through 68 weeks of age.

Effects of ad libitum and restricted (50% of ad libitum) feeding on performance of female broilers were assessed in a 68-week experiment. The treatments imposed were AA, fed ad libitum throughout; RR, fed restricted amounts of feed throughout; RA restricted through 24 weeks of age and ad libitum thereafter; and AR, fed ad libitum through 24 weeks and restricted thereafter. Average age at first egg was delayed by 17 days in RA hens compared with AA hens. Average body weight at first egg was 3.9 kg for RA birds and 4.5 kg for AA birds. Peak production was higher for RA birds (71 vs. 59%), but age at peak production was similar for both AA and RA hens. Through 68 weeks, AR birds produced 50% more eggs than AA birds (159 vs. 106). Cumulative number of eggs produced for RR and AR birds were 37 and 47, respectively. Mortality was similar for RR, RA, and AR birds but was approximately fourfold greater in AA birds. At 68 weeks of age, live body, carcass, abdominal fat pad, and estimated fat-free carcass weights were similar for AA and RA birds. Although abdominal fat as a percent of carcass weight was similar for AR and RR birds, average live weight, carcass weight, and fat-free carcass weight were higher for AR than RR birds at 68 weeks.