Rearing Leghorn Pullets on a Photoperiod of 1 Hour of Light and 11 Hours of Darkness with Respect to Growing and Laying Performance as Influenced by Age at Housing and Strain

Two trials in two years, each involving 2 commercial strains of White Leghorns, were conducted to compare the growing of Leghorn pullets on: (1) one hour of light and 11 hours of darkness (1L:11D) from day 4 to housing; vs. (2) a program of 8 hours of light and 16 hours of darkness (8L:16D). Lighting treatment had a significant effect on body weight in trial 1 with birds grown on 8L:16D being heavier at 4 and 8 weeks of age, while those grown on 1L:11D were heavier at 16 weeks of age. Birds grown on 1L:11D did consume less feed to 20 weeks than those grown on 8L:11D in trial 1 (6.24 kg. vs. 6.61 kg.) and in trial 2 (6.75 kg. vs. 7.60 kg.) where the effect was significant (P<0.05). Birds grown on 1L:11D had a greater age at 50 percent production in both trials. In trial 2, it was found that this effect could be modified by housing birds at different ages. There was no effect of lighting program during the growing period on subsequent percent egg production in trial 1 though in trial 2 the effect was significant (P<0.05) (1L:11D, 77.2% vs. 8L:16D, 75.8%) as was the interaction of lighting treatment by strain (P<0.05). There was no effect of lighting treatment on kg. of feed per dozen eggs, but in trial 2 birds grown on 1L:11D laid significantly (P<0.05) heavier eggs. Birds grown on 1L:11D showed a greater return over feed and chick costs for one strain in trial 1 and for both strains in trial 2 at an average of 30 cents per bird. In neither case were the differences significant.