The Relationship of Egg Shape to Time of Oviposition and Egg Shell Quality

Abstract

Experiments were conducted to determine the relationship of egg shape to time of oviposition and egg shell quality. Eggs were collected at 2-hr intervals throughout the day and depending upon the experiment various measurements (egg weight, shape index, shell weight, shell thickness, or specific gravity) were determined.The results indicated that eggs laid during the afternoon had a higher shape index (rounder eggs) than eggs laid during the morning. The afternoon eggs also had a higher specific gravity, shell weight, shell thickness, and were smaller than eggs laid during the morning. A large variation in shape index occurred among eggs.It was concluded that the difference in shape between times of oviposition would not explain the variation in shell quality due to time of oviposition, but that the large variation in egg shape among birds is a significant factor in determining the bird’s ability to produce eggs with maximum shell thickness with a given amount of shell.