Structure of Hen Eggs and Physiology of Egg Laying

This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book describes, briefly, the structure of hen eggs and the process of laying eggs. A hen egg is composed of three main parts: shell, albumen (egg white), and yolk. The eggshell membrane is composed of inner and outer membranes. Their structure is like entangled threads or randomly knitted nets. The egg albumen portion consists of thin and thick albumen and a chalaziferous layer. Thick albumen is sandwiched between outer and inner thin albumen. The chalaziferous layer is a fibrous layer and directly covers the entire egg yolk. The egg yolk is encircled by a vitelline membrane. Structurally, the inner content consists of yellow yolk and white yolk. The vitelline membrane is composed of an inner layer, continuous membrane, and outer layer. When yellow yolk is accumulated sufficiently, the follicle in the ovary is ovulated into the oviduct.