Consequence of increased feed allowance for growing broiler breeder pullets as a means of stimulating early maturity

Two hundred and forty Hubbard X Hubbard breeder pullets, 3 weeks of age, received conventional quantities of feed according to the breeder's recommendation or 5, 10, or 20% extra feed allowance. On reaching an average weight of 2.1 kg, birds were moved to laying cages, subjected to 14 hr of light per day, and offered a breeder diet at the breeder's recommended allowance. Increased feed intake resulted in increased growth rate such that control, +5, +10, and +20% groups reached 2.1 kg liveweight at 20, 18, 18, and 16 weeks, respectively. Total feed intake was significantly less to 2.1 kg liveweight for the younger birds. The early move to the laying house subsequently resulted in early maturity. However, these birds failed to show persistency of production after peak, there being a 10% decline within a 4-week period. Control reared birds, starting production at 23 weeks, exhibited a more conventional and persistent peak egg production. There was an indication that early maturity adversely affected egg size. The significant saving in pullet feed cost warrants further trials aimed at elucidating the mechanisms affecting persistency of production in early maturing broiler breeders.