Influence of selection for increased egg production, body weight, and shank width of turkeys on egg composition and the relationship of the egg traits to hatchability.

Egg traits, mature BW, fertility, and hatch of fertile eggs were measured in lines of turkeys selected for increased egg production, increased 16-wk BW, and increased shank width and in corresponding randombred controls to determine the effects of selection. Genetic increases in egg production were associated with decreased mature BW and egg weight with no change in fertility or hatchability. The decrease in egg weight was associated with a proportional decrease in the albumen, shell, and yolk. Genetic increases in BW were associated with increased mature BW and egg weight and decreased fertility and hatch of fertile eggs. The increase in egg weight was primarily due to an increase in albumen. Selection for increased shank width had little influence on egg traits. Fertility and hatch of fertile eggs were correlated. Hatch of fertile eggs was positively correlated (after the effects of line were removed) with absolute and percentage shell and percentage yolk and negatively correlated with percentage albumen. The regression coefficients of egg weight on mature BW differed between lines, with the relationship being larger in smaller lines.