Incubation Characteristics of Eggs from Older Small White Turkeys with Emphasis on the Effects due to Egg Weight

Abstract

Two commercial breeder flocks of Small White turkeys (Diamond White) that were older than average (48 and 55 weeks of age), each provided 4000 eggs from one and the same day's collection. All eggs were individually weighed and based on their frequency distribution separation into 4 categories, respective of flock. A total of 6912 eggs were set in one incubator. Apparent fertility, weight loss with incubation, germ deaths, poult weight, and sex distribution were monitored.

Absence of statistically significant interactions between source and weight of the egg permitted orthogonal comparisons of the flocks apart from egg weight categories. Reduction in hatchability of total eggs set with increasing breeder age could largely be attributed to infertility and/or very early blastodisc death. Incidence of non-viable germs is greater with very large eggs which, in turn, occupy progressively greater proportions of total eggs laid. No significant differences in hatching success between weight categories occurred with viable eggs. Losses in weight with incubation were largely influenced by the weight of the egg where heavier eggs lost proportionately less than smaller ones. Males outnumbered females regardless of flock source or egg weight category with poult weights of both sexes paralleling that of the egg. Overall evidence suggests that viable eggs are more likely to hatch if they originate from fresh eggs having a high albumen height than if internal quality was low.