Colours of Chicken Eggs 101
All chicken eggs are white at first.
Look inside a brown egg the next time you crack it open; you’ll see that the interior is white. This is so that just the shell’s exterior may contain any colour that is applied to an egg.
The egg’s shell gains colour as it passes through the hen’s reproductive system.
Pigment is used to put the colour onto the egg shell. The two primary pigments that we are aware of are oocyanin and protoporphyrin IX (brown) (blue). You may have hens who produce eggs that are green, pink, or even purple, but these hues are all the result of a protoporphyrin IX and oocyanin mixture that is placed on top of a white egg.
Brown eggs only have protoporphyrin IX, whereas blue eggs only have oocyanin deposited on them. The quantity of pigment layers will affect the tone of these colours. As contrast to numerous layers of a single pigment, which will deepen the colour, a coloured egg will only have a few thin layers of colour.
Therefore, blue eggs do not inherently contain protoporphyrin IX, despite the fact that many hens do. With the introduction of a contagious retrovirus that permanently changed the DNA of some breeds, blue eggs were introduced. Blue eggs are entirely safe to eat, so don’t worry.
Simply put, this retrovirus altered the colour of the eggs.
The Araucana and the Ameraucana are two breeds that were impacted by this retrovirus and now naturally possess the oocyanin pigment. You may have heard of them before.
What shades of eggs can chickens produce?
It is practically a given that if you have ever eaten eggs, you have cracked open a traditional white egg. White is the most typical egg colour naturally out of all the other hues. The origin of this egg hue is also the simplest to explain.
White eggs are devoid of coloration, unlike the other egg hues on this list. The oviducts of white egg-laying chickens simply do not experience the pigment layer process. Since calcium carbonate, the mineral that makes up most of the eggs, is naturally white, the eggs are white.
Brown eggs are the most popular colour after white eggs. The brown egg shells are caused by the pigment prototoporphyrin IX.
Many hens spontaneously manufacture protoporphyrin IX, which is then released onto the egg as it passes through the oviduct. It is applied to the egg in several layers because applying it in fewer layers would result in coloured rather than fully browned eggs.While chocolate brown eggs are far more uncommon, brown eggs are often thought to be more of a tan to medium brown tone.
In the field of poultry, the chocolate brown egg hue is uncommon. A chocolate brown egg may add a lot of color to your basket even if not many birds can lay them. Marans are becoming more and more well-known, and they are valued for their chocolate-brown eggs.
Protoporphyrin IX still coats the white egg in the oviduct, giving it the chocolate brown hue. The deep chocolate coloring is caused by the presence of more layers of the pigment than usual in brown eggs.
Compared to white or brown eggs, blue eggs have an entirely different history.
After contracting a retrovirus, chickens developed blue-shelled eggs due to a genetic alteration that occurred inside the infected animals. The dominant oocyan allele replaced the former, non-blue gene as a result of the mutation of chicken chromosome 1.
The pigment responsible for the blue hue of eggshells is known by the term oocyan. While oocyan substitutes protoporphyrin IX in this pigmentation process, it still works the same manner in brown eggs.