Interactive Effects of Layer Breeder Strain and Egg Shape on Hatching Egg and Eggshell Characteristics

Understanding how breeder strain and egg shape interact to influence hatching egg and eggshell characteristics and hatchability is essential for improving incubation efficiency. The objective of this study was to investigate influence of layer breeder strain, egg shape and their interactions on hatching egg and eggshell characteristics.

In this experiment, two strains and three egg shapes were studied. Individual egg weights were recorded before incubation using a precision electronic balance (±0.01 g). The same eggs were reweighed on day 18 of incubation to calculate weight loss during the incubation period. Egg volume (EV), total pores per egg (TP), shape index (SI), shell weight (SW), shell percentage (SP), shell index (SHI) and hatchability percentage were also recorded.

Percentage of egg weight loss was significantly greater in rough-shelled (10.76%) and abnormally shaped eggs (10.25%) than in normal ones, which showed the lowest loss (8.98%). In terms of interaction effects, all possible interactions significantly influenced egg weight at both day 0 and day 18 of incubation, as well as absolute and relative egg weight loss during incubation. Breeder strain had a significant effect on egg volume (EV), total pores per egg (TP), shell percentage (SP) and shell index (SHI). White eggs exhibited a higher number of pores (7258) compared with brown eggs (6979) and abnormally shaped eggs also had more pores overall. In contrast, brown eggs showed significantly higher shell percentage and shell index values than white eggs. Among egg shapes, normal eggs had the highest shell percentage and shell index, while eggs with rough shells demonstrated the lowest hatchability rates in both brown and white strains.