Characterization of Incubational Egg Weight Losses in Three Types of Turkeys ,

Incubational egg weight losses of eggs from three types of turkeys were compared three times during a 20-week laying period to determine how increased egg weight affects the water vapor loss of turkey eggs during incubation. One type of hens selected was Large White recycled hens (LW2) in which preincubation egg weight was constant throughout the laying period, whereas the remaining two types, Large White first cycle (LW1) and Small White first cycle (SW1) hens, were selected such that preincubation egg weight increased during the laying period. The LW1 turkey eggs lost the greatest percentage of their preincubation egg weight, SW1 turkey eggs were intermediate, and LW2 turkey eggs lost the smallest percentage. Turkey eggs laid early in a laying period lost less weight than eggs laid in the middle portion, and eggs laid in the mid portion lost less weight than eggs from the late portion. The amount of water vapor lost per unit of shell area as well as the shell conductance data were similar for all hen types and times of the laying period. Increases in preincubational egg weight, egg surface area, and their resulting increased incubational egg weight losses occurred principally during the first 10 weeks of the egg production period in both LW1 and SW1 hens’ eggs.