Eggs are produced by females of many different species, including birds, reptiles, amphibians, mammals and fish, which have been consumed by humans for thousands of years. Eggs of birds and reptiles are composed of protective shells, proteins (egg whites) and yolks (yolks), which are contained in various membranes. The most popular choice for egg consumption is egg. Other popular choices for eggs are duck, quail, caviar and caviar.

Yolk and whole egg store a lot of protein and choline, which are widely used in cooking. Due to its high protein content, the U.S. Department of agriculture classifies eggs as "meat" in the "food guide pyramid". Despite the nutritional value of eggs, the quality, storage and individual allergies of eggs can still cause some potential health problems.

Chickens and other spawning organisms are widely raised around the world, and the large-scale production of eggs is a global industry. In 2009, around 6.4 billion hens worldwide produced an estimated 62.1 million tons of eggs. There are regional differences in demand and expectation, as well as current debates on mass production methods. In 2012, the EU banned chickens from raising batteries.