Wild junglefowl lay about a dozen eggs a year; modern hens manage over 300
The wild Asian fowl behind today's chickens lay roughly a dozen eggs a year, and only in breeding season. Thousands of years of selective breeding produced hens that lay more than 300 a year, all year round. By 2023 the world was producing 91 million tonnes of hen eggs annually.
Chickens were probably domesticated for eggs rather than meat, from junglefowl of tropical Asia and the Indian subcontinent, sometime before 7500 BCE. They reached Sumer and Egypt by about 1500 BCE and Greece around 800 BCE, where quail had supplied most eggs until then. A tomb at Thebes from about 1420 BCE shows a man carrying bowls of ostrich eggs as offerings, and Roman dinners often opened with an egg course.
Medieval Europe banned eggs during Lent for their richness, but the fast had a practical side: it let farmers rest their flocks and save feed when stores ran low. Seventeenth-century French cooks scrambled eggs with acidic fruit juice, a possible ancestor of lemon curd. A St. Louis firm began drying eggs into a brown powder in 1878, and in 1911 Joseph Coyle of Smithers, British Columbia, invented the egg carton to settle a row between a farmer and a hotel owner over broken eggs.
An egg records its own age. As water escapes through the shell, air is drawn in and the cell at the broad end grows, which is why graders shine a light through eggs, a process called candling, to award AA, A or B, and why an old egg floats. Shell colour tracks the hen's ear lobes, white lobes usually meaning white eggs, and has no meaningful link to nutrition. Yolk colour comes from plant pigments in feed such as yellow maize or marigold petals; lutein is the main one.
Cooking changes more than texture. The protein in a cooked egg is about 91 percent bioavailable, against 51 percent raw. Whites are around 90 percent water with 10 percent protein and almost no fat, which lets them foam into meringue; yolks act as emulsifiers and thickeners. Egg whites are also used in making some vaccines, including those for influenza.
Source: Eggs as food
