Effect of Dry-Bulb Temperature, Relative Humidity, and Eggshell Conductance During the First Three Days of Incubation on Egg Weight Loss and Chick Weight

Abstract

Broiler hatching eggs of similar weight were randomly divided into three groups. The first group of eggs served as the control, the second group was washed in sodium hypochlorite to disrupt the cuticle, the third group was dipped partially in a colloid solution to seal the pores in the pointed region of the eggshell. These treatments altered eggshell conductance, measured as milligrams of water loss per day per torr, from Day 2 to Day 3 of incubation. Eggs from all three groups were randomly placed in incubators operating at a dry-bulb (DB) temperature of 36.7, 37.2, or 37.8 C and at a relative humidity (RH) of 59% (Experiment 1), or at an RH of 51, 59, or 67% at a DB temperature of 37.2 C (Experiment 2) for the first 3 days of incubation. At the end of Day 3 of incubation, all eggs were transferred into an incubator operating at a DB temperature of 37.2 C and at 59% RH for the remainder of the incubation period. Individual egg weights were recorded on Days 1, 2, 3, and 18, and at external pipping. Chick weight at hatch and eggshell weight were also recorded.The incubating DB temperature had no effect on egg weight loss from Day 0 of incubation to external pipping. However, a DB temperature of 37.8 C produced significantly heavier chicks at hatch, when the chick weight at hatch was expressed as a percentage of initial egg weight. A relative humidity of 51% resulted in the greatest weight loss from Day 0 to Day 1 and from Day 2 to Day 3 of incubation, and the least weight loss from Day 1 to Day 2 of incubation. Eggs treated with colloid and chlorine lost significantly more weight from Day 0 to Day 1 of incubation; however, the colloid-treated eggs lost significantly less weight from Day 2 of incubation to external pipping. The colloid-treated eggs produced heavier chicks at hatch.