The Influence of Increased Uniformity of Body Weight in Pullets at 19 Weeks of Age on Subsequent Production

Abstract

Day-old pullets (Hisex-strain Leghorn) were fed a starter ration ad libitum to 10 weeks of age. Individually weighed at 9 weeks of age they were sorted into 3 weight groups. Treatment 1, from the smallest weight group, was full-fed from 10 to 19 weeks of age. Treatment 3, from the middle third, was full-fed initially then restricted as necessary to maintain the recommended weight. Treatment 4, from the heaviest third, was restricted to attain the recommended weight at 19 weeks of age. Treatments 2 and 5 represented random samples of equal numbers from each weight. Pullets in treatments 2 and 5 were full-fed and restricted-fed, respectively.Differences which existed among the mean weights of treatments 1, 3, and 4 at 9 weeks of age decreased to 15 g at 19 weeks. At 19 weeks of age the pullets in these treatments averaged 80.7% to 84.0 ± 10% of the average weight.At 19 weeks of age, 96 pullets per treatment were further divided into eight replicates and transferred to layer cages. Pullets in treatment 4 (heaviest third, restricted-fed) were significantly older when reaching 10 and 50% production than were pullets in treatments 1, 2, and 3. The mean egg weights of pullets in treatments 4 and 5 were larger (P<.01) than those from the other treatments.Differences among treatments in hen-day production, gram of egg per hen day, grams of feed per gram of egg, feed per hen day, Haugh units, shell thickness, and mortality were not significant.