Restricted feeding in early and late-feathering chickens. 1. Growth and physiological responses.

Broiler-breeder females from a parent stock segregating for early and late feathering were fed ad libitum (AL, feed was always available), ad libitum restricted (ALR, feed restricted daily to control body weight), skip-one-day and skip-two-days (SOD and STD, given two or three times ALR allowance on Day 1 and not fed on the next 1 or 2 days, respectively). At 160 days of age, pullets on SOD and STD were changed to ALR feeding, and daily feed allowances were increased to 135 g by Day 180 and 138 g by Day 250. Responses of early and late-feathering females were similar for traits measured. Generally, body weights of AL chickens increased to 4,600 g at 130 days of age and then reached a plateau. Body weights of feed-restricted groups were less than half of that of AL chickens by 160 days of age. Controlled release from feed restriction enabled chickens to reach a weight of approximately 3,200 g by Day 210. Daily feed consumption for AL chickens increased to about 220 g by 140 days of age and then decreased to approximately 150 g by Day 250; it eventually decreased to approximately 120 g by Day 350, where it reached a plateau. Mortality, plasma glucose levels, and surface and cloacal temperatures were lower for females whose feed was restricted than for those fed AL. Plasma protein levels were greater for STD than for AL, ALR, and SOD groups whereas plasma lipids were higher for AL and SOD than for ALR and STD groups.(ABSTRACT TRUNCATED AT 250 WORDS)