Effects of ad libitum versus restricted feeding on body composition and egg production of broiler breeders.

A 64-wk experiment was conducted in which the effects of ad libitum vs. restricted feeding were studied during the pullet-layer transition and laying periods. Broiler breeder females were reared through 23 wk of age according to the breeder's recommendation. At 24 wk of age the following four treatments were imposed: T1, fed restricted amounts of feed according to the breeder's management guide; T2, feed restricted from 24 to 32 wk of age (as in T1), then fed ad libitum; T3, fed ad libitum from 24 to 64 wk of age; and T4, fed ad libitum from 24 to 32 wk of age, then restricted to 85% of the average 24 to 32-wk consumption. Birds fed ad libitum during the pullet-layer transition period (T3 + T4) consumed an average of 37 g more feed per day and reached sexual maturity 14 days earlier than restricted birds (T1 + T2). Live body weight, carcass weight, carcass weight corrected to zero fat content, and percentage carcass fat were all significantly higher at first egg in ad libitum vs. restricted birds, but these differences were small. Birds fed ad libitum during lay (T2 + T3) produced more eggs, achieved a higher peak percentage hen-day production, consumed more feed, and contained more body fat at last egg than hens restricted during lay (T1 + T4). However, neither mortality, feed efficiency, egg weight, egg fertility, nor egg specific gravity was affected by treatment.