Body Weight Influence on Egg Production

Abstract

Five hundred seventy-six Single Comb White Leghorn pullets were divided into three body size categories at 20 weeks of age and assigned to laying cages for a 52-week production period. Average body weight of the heavy, medium, and light size groups were 1377, 1256, and 1131 g, respectively. Size of bird did not affect age at 50% production, hen-day or hen-housed production. Livability of the heavy birds was significantly lower (16.2 and 15.6%) than livability of the medium and light birds, respectively. Body weight differences at 20 weeks of age continued through 72 weeks of age. Heavy birds produced heavier eggs, consumed more feed per hen day, and consumed more feed per dozen eggs than the medium and light birds, while the medium birds had greater means than the light birds for each of these categories. The heavy birds also consumed 3.66% more feed/g egg mass than the light birds. The results of this experiment indicate that chickens can produce at lighter body weights than in the past, therefore, nutritional programs which produce lighter pullets may be desirable.