Pimpling of egg shells and hatchability in several strains of turkeys

Eggs from several strains of turkeys (two randombred control populations of different origin and differing greatly in body weight and several sublines of these control strains selected for various traits) were scored for the amount of egg shell pimpling over a 12-week hatching period. The frequency of pimpled eggs averaged 15.6% in the medium-bodied strains and 21.2% in the large-bodied strains. The two randombred control strains, based on hen averages, did not differ significantly from each other, nor was there any significant difference among medium-bodied strains for pimpling scores. A large-bodied subline selected for decreased broodiness had a higher pimpling score than its corresponding randombred control. There were no other significant differences among the large-bodied strains. These data suggest that there is either little genetic variation in egg pimpling or little association between egg pimpling and traits for which selection was practiced (egg production, 16-week body weight, blood level of corticosterone after cold stress, clutch length, fertility, or plasma level of estrogens during the laying period). Pimpling increased with length of the hatching period. There was a small but significant correlation coefficient (-.11) between pimpling score and hatch of fertile-eggs. There was no significant association between pimpling score and percent 7-day incubation weight loss.