Researchers selected Japanese quail for larger and smaller eggs over multiple generations. While selection for smaller eggs continued, larger egg size quickly reached a plateau. This review explains what the findings reveal about genetics, selection, and the limits of egg size evolution.

Can you breed stronger eggshells? This research review examines how genetics influences egg weight, shell strength, shell quality, and heritability in Japanese quail—and what the findings mean for selective breeding.

Egg size is influenced by many genes—not just one. This research review explains how scientists mapped chromosome regions affecting egg weight, shell quality, yolk characteristics, and production traits in Japanese quail, and why those discoveries matter to breeders.