EFFECTS OF EGG WEIGHT ON POSTHATCHING GROWTH RATE OF BROILER CHICKS

Abstract

Eggs obtained from a commercial broiler hatching-egg producer were assigned by weight to seven groups and set for hatching. After hatching, equal numbers of male and female chicks were placed in floor pens according to egg weight groups and weighed at day-old and weekly for 8 wk. Three additional groups of chicks consisted of: equal numbers of females from each egg weight group; equal numbers of males from each egg weight group; and equal numbers of males and females from each egg weight group. Analysis of the data indicated that the influence of egg weight on chick weight decreased with time. Significant differences in body weight among groups occurred for all ages for the females, whereas no significant differences occurred for the last two ages for the males. Chicks grown in the mixed egg weight groups did not differ from those grown separately. Even though statistical evidence indicated that egg weight did influence 8-wk body weight of females, factors such as cost of producing hatching eggs, price of day-old chicks, hatchability of eggs, length of growing period, and availability of hatching eggs, would have to be taken into consideration before deciding whether or not smaller eggs could be used profitably in the industry.