Eggs Galore: Why Chicken Eggs Have Different Colors

By: Jordan Walker, Coops and Cages -

Jordan Walker is fond of animals is an understatement; he is passionate about them. His expertise in all animal and pet-related matters is a welcome addition for this blog’s readers. Jordan also writes content for Coops and Cages. In this article, he brings little-known facts to light regarding the age-old question—why do chicken eggs have different colors?

One thing we need to know about the humble chicken egg is this: egg color is determined primarily by the genetics of the hens. Another important thing is that color does not affect the quality of chicken eggs. Chicken eggs are the most accessible, most abundant, and easiest type of eggs to cook with. Just head to the nearest grocery or farmer’s market and they’ll definitely have an array of chicken eggs to choose from—there’s free range, grade A, grade AA, organic, vegetarian, and vitamin-enriched just to name a few. But what most probably stumps you is why chicken eggs come in different colors and what do these colors mean, or if they affect anything quality-wise.

It’s all in the hen genetics

According to a study by the Michigan State University Extension, it is the genetics of the hens that determine egg color. Generally, hen breed indicates what color of egg will be produced. Typical snow white egg laying breeds include Andalusians, Dorkings, Faverolles, Lakenvelders, and Leghorn chickens. Breeds like Barnevelders, Delawares, Jersey Giants, Orpingtons, and Rhode Island Reds lay eggs varying from cream to dark brown. Araucanas are known for laying light blue eggs, while Olive Eggers lay, yup, you guessed it—olive-colored eggs. Color is not an indication that a certain colored egg is healthier than other colors, nor does it also affect taste. In fact, unlike what most believe, a brown chicken egg isn’t healthier than a white chicken egg. Also, it is the chicken’s diet which determines the taste of the egg once it’s cooked. Ultimately, your egg purchasing decisions shouldn’t be affected by the color of the egg.

White ear lobes give it away

There’s another easy tip you can use to determine what color of eggs your hens will produce. Look at the hens’ ear lobes. In most cases, chickens with white ear lobes produce white eggs, while some chickens with red ear lobes produce brown eggs. However, this indication is not set in stone.

In the beginning, everything was white, then came pigments

You probably don’t know this yet—all eggs start out white in color. Yes, you read that right. Eggs that turn out in different shades other than white become so because of pigments deposited on them when they travel through the hen’s oviduct. The oviduct is a tube-like organ through which the egg passes through from the ovary and gets laid. The entire egg-laying process takes place for 24-26 hours, from which 20-21 hours goes to the formation and solidification of the egg shell, including the addition of pigments.

For chickens that lay brown eggs, the pigment protoporphyrin is deposited on the eggs during the last stages of shell forming. This pigment only tints the outside surface of the egg and does not penetrate through the interior, that’s why the interior of the shell is white. For Ameraucana hens that lay blue-tinted eggs, the pigment oocyanin is deposited on the egg as it travels through the oviduct. This pigment penetrates through to the interior, and that’s why the egg’s shell is blue inside and out. In the case of Olive Egger hens, a brown pigment covers a blue egg shell, resulting in an olive, or greenish tinge. The darker the brown pigment is, the more olive the egg is in color.

Selective breeding: The human influence

One other explanation for the differences in chicken egg colors can be traced back to human influence. Ever since humans have discovered selective breeding in animals, this has resulted in genetic changes or mutations in them that occur over time. What used to be common before were brown-colored chicken eggs fresh out of farms, but years of selective breeding has allowed for the production of white chicken eggs, which have now become the norm in the market. Another example is the Araucana breed, a chicken breed originally from Chile, which have been cross bred to produce the Ameraucana breed. The latter is also known as the “Easter egg chicken” due to its delicate blue or green-tinted eggs, sometimes used for Easter egg hunts and Easter-themed décor.

Brown eggs were re-introduced in the market fairly recently—by the end of the 20^th century, although most farmers and farm owners are already familiar with them. These days, it’s mostly marketed as a more natural or organic kind of egg, hence its appeal to the more health-conscious type of consumers.

Referenced Links:

1. – about other ways to use up eggs when you have a lot of them (from The Sleuth Journal website)
2. – about the benefits of consuming free-range chicken eggs
3. – a helpful chicken chart to determine info such as egg color based on a breed, breed origins, etc.
4. – about foods you should not feed to your chickens (from The Sleuth Journal website)

Jordan Walker is the lead content curator for Coops And Cages as well as a couple of other pet related blogs. His passion for animals is only matched by his love for ‘attempting’ to play the guitar. If you would like to catch him, you can via Google+ or Twitter: @CoopsAndCages.