Eggshell quality is associated with hatchability, and ultrastructural organization is an important eggshell quality parameter. To the determine the relationship of shell ultrastructural properties with hatchability, we measured the effect of eggshell thickness, mammillary layer thickness, and the average size of mammillary cones on hatchability. Eggs with thick shells and thick mammillary layers had the highest incidence of hatching. As such, hatchability correlated positively with both eggshell thickness (r = 0.30; P < 0.05) and mammillary layer thickness (r = 0.28; P < 0.05). In addition, the correlation between the average size of mammillary cones and hatchability was not statistically significant. However, a significant positive correlation was observed between the average size of mammillary cones and mammillary layer thickness. It can be concluded that eggshell thickness and mammillary layer thickness affect hatchability.