What determines what color an eggshell is? DNA plays a major role.

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4 min readMay 23, 2022

In everyday life we are not particularly interested in them, and it is only at Easter when they start to attract our attention. Then we like to paint them, transforming them into Easter eggs. But is it necessary? Hen eggs can have very different colors by nature.

[Photo by Anna Tis, Pexels]

Eight thousand years ago in the jungles of southern Asia lived a small bird that made its nests in thickets and fed in open areas. The male had a distinctive red crest and a shiny black tail. The female was smaller and more uniformly colored. She laid 8 to 12 eggs, from which chicks hatched after only three weeks.

The fact that these birds flew infrequently and rather low, and that their eggs were nutritious, probably encouraged our ancestors to domesticate them. Today they have a scientific name — they are the banked hen (Gallus gallus). The banked hen is believed to be the ancestor of the domestic hen.

How many breeds of hens are there in the world?

If you look at the numbers, chickens have achieved great evolutionary success. Currently, there are almost twenty billion of them on Earth. However, for the absolute most part, they are animals raised by humans for food. They bear little resemblance to their colorful ancestor — these are white hens of the Leghorn breed.

However, a hen is not equal to a hen. Since the time of domestication, people often crossbred hens of different breeds, and even coming from different continents. As a result, in the world today we have more than two hundred different breeds of hens, differing in size, plumage, carrying capacity. And also the color of the eggs they lay.

What does the color of eggs depend on?

The color of the shell of an egg laid by a hen depends on her breed. That is, the genes. And these genes allow the hens to produce eggs in a wide variety of colors.

One of the most famous chicken breeds is the Marans. It comes from France and the eggs that it lays have a dark brown color, sometimes resembling chocolate. In the Dutch village of Welsum, on the other hand, a breed of hen was bred in the early 20th century, which lays brown spotted eggs.

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