Welcome to the The Incredible Edible Egg™ Eggcyclopedia, where you can access the latest egg information from A-Z. The Eggcyclopedia was developed by the American Egg Board (AEB) on behalf of America's egg farmers who are committed to caring for their hens and producing high-quality eggs for you and your families.

Just click on any letter below to bring up a list of egg terms and their related definitions.


Several factors influence the size of an egg. The major factor is the age of the hen. As the hen ages, her eggs increase in size. The breed of hen from which the egg comes is a second factor. Weight of the bird is another. Pullets significantly underweight at sexual maturity will produce small eggs. Environmental factors that lower egg weights are heat, stress, overcrowding and poor nutrition. All of these variables are of great importance to the egg producer. Even a slight shift in egg weight influences size classification and size is one of the factors considered when eggs are priced. Careful flock management benefits both the hens and the producer. – See Buying, Grading, Production, Treatment of Hens