Why are some chicken eggs white and some eggs ‘brown’ or ‘speckled’? Is it related to why supermarkets sell mainly packages of eggs of the same shape and colour per package and why those packages are all differently priced?



When I say differently priced I mean by egg ‘quality’ (like free range vs caged, although I’m not sure the exact mechanics of how that correlates to egg quality; I can imagine it impacting flavour though – happy chicken, yummy eggs?) not by the number of eggs sold per package, although that may have something to do with pricing, who knows?

In: Biology

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According to Michigan State University Extension, egg color is determined by the genetics of the hens. The breed of the hen will indicate what color eggs she will produce. For example, Leghorn chickens lay white eggs while Orpington’s lay brown eggs and Ameraucana produce blue eggs. An Olive Egger, a chicken that lays olive green eggs, is the product of a cross between a hen and rooster that are from a brown egg and a blue egg laying breed. An interesting tip is to look at the chicken’s ear lobes; typically those with white ear lobes produce white eggs.
All eggs start out white in color; those that are laid in shades other than white have pigments deposited on them as the eggs travel through the hen’s oviduct. The journey through the chicken’s oviduct takes approximately 26 hours. The shell takes roughly 20 hour to be complete. Ameraucana birds have the pigment oocyanin deposited on the egg as it travels through the oviduct. This pigment permeates the egg shell resulting in the interior and exterior of the egg being the same blue color. Chickens that lay brown tinted eggs deposit the pigment protoporphyrin on the eggs late in the process of forming the shell. The pigment therefore does not penetrate the interior of the egg, but tints only the surface of the egg, which is why brown eggs are white on the interior. In the case of an Olive Egger, a brown pigment overlays a blue egg shell resulting in a green egg. The darker the brown pigment the more olive color of the resulting egg

Most of the time, assuming the eggs are from chickens being raised properly, there’s no discernible difference in nutrients between the different egg colors. However people like their nice, white eggs so will pay more for those. So the store charges more for what people are going to buy.

There’s no difference in the egg it’s just genetics it’s like asking why someone has black or white skin or freckles. The only reason white eggs are more common and more expensive is because people associate whiteness with cleanliness.

For whatever reason the hens laying white eggs have been selectively bred for higher production rates.

A white leghorn hen is likely to lay an egg every day thru the 6 month ‘best production’ cycle of life.

Hens laying the colored eggs have not been bred up to the same extent, a hen may lay 5 or 6 eggs a week during peak production. In a factory setting it’s more profitable to keep the white egg layer as both birds occupy equal space and eat equal feed over the same time period.

RE free-range, cage free designation – Factory hens are kept in tiny cages and fed 100% artificial food. The feed needs to be as economical as possible and still produce results.

Chickens ranging outdoors find a variety of nutritious foods that chickens are **designed** by evolution to eat. eating a variety of natural foods along with fresh air and exercise produce more nutritious, tastier, and harder shelled eggs but require a more intensive management (hands on) by the farmer and the equipment and space required are different from the factory setting.