RESPONSE OF BROILER BREEDER HENS TO FORCED MOLTING BY HORMONAL AND DIETARY MANIPULATIONS

Experiments were conducted to compare dietary and hormonal techniques for molting broiler breeder hens. In the first experiment, production dropped to 5% 3 wk after hens were restricted to an intake of one half of their calculated energy requirement (FR). Egg production levels of hens given a single i.m. injection of the Lupron Depot(R) formulation of leuprolide acetate (LA) in a dose intended to provide 10 mu g/kg BW per d for 30 d dropped to 9.5% whereas production dropped to 33% in hens receiving 5 mu g and was unchanged by 2.5 mu g. Postmolting fertility and hatchability of eggs from the FR and the 10-mu g LA groups were not different. In the second experiment, postinjection egg production, oviduct weight, and uterus weight were depressed, in a dose-related manner, when hens received 0, 10, or 22 mu g LA/kg per d. In a third experiment, egg production dropped to zero within 2 wk when hens were deprived of feed (FD) or deprived of feed and light (FD + LR), whereas it reached zero in 4 wk in hens fed only 30 g of wheat shorts per d (FR). Lupron Depot(R) at a dose intended to deliver 30 mu g/kg BW per d, reduced egg production to 9.5% by the 3rd wk. Twenty-eight weeks postmolting, egg production ranged from 84 to 98 eggs per hen in the molted groups and 56 eggs per hen in the unmolted controls. Fertility ranged from 82.1% in the FD + LR groups to 69.8% in the unmolted controls, whereas chick production averaged 36, 50, 59, 60, and 68 chicks per hen in the unmolted controls and in hens molted by LA, FR, FD, or FD + LR, respectively.