I recently saw something I had never seen before – blue and green chicken eggs! And I wondered, why do chickens lay different colored eggs?
Now, I don’t have chickens due to municipal codes in my city, but I did some research. The color of the egg is linked to the genetics of the chicken. Simply put, different breeds of chickens lay different colored eggs. There are several different chicken breeds and lots of different colored eggs out there, so let’s dig deeper into what I found.
Different breeds of chickens
There are so many different chicken breeds out there – everything from the big egg-laying Leghorns to the meaty birds like Cornish Cross or Jersey Giant. For eggs, however, some breeds are simply better than others.
For standard white eggs, the most common breed is the White Leghorn. They’re known better for their egg-laying capabilities rather than their size; they weigh in at a mere 5 pounds on average. These hens will produce a whopping 280 to 300 eggs in a single year. That’s a lot of quiche!
Common brown egg layers include Rhode Island Reds, New Hampshire Reds, and Plymouth Rocks. It’s also interesting to note that New England typically purchases more brown eggs than any other region in the United States.
For eggs of more interesting colors, there’s the popular Ameraucana. Known for their blue eggs, these chickens were bred from Auracanas in an effort to retain the egg color while eliminating genetic issues. Ameraucanas are nicknamed the Easter Egg Chicken because of the bright blue hues to their eggs. On average, Ameraucana hens will lay about 250 eggs per year.
And still, there are plenty of other breeds with even more colors. One in particular – the Olive Egger – was bred specifically to create a new color of egg. This breed stems from crossing a blue layer such as the Ameraucana with a dark brown layer such as Welsummers.
How a chicken egg is formed
No matter the breed, all chickens create eggs the same way.
No, not that way.
Chicken eggs start out as immature yolks in the hen’s ovary. Upon reaching maturity, the ovary releases the yolk into the oviduct when the hen ovulates. It’s at this point the yolk needs to be fertilized in the infundibulum. The yolk then travels through the magnum, where it builds albumen layers – a process that takes about 3 hours to complete.
After the magnum, the egg moves to the isthmus. The egg can spend up to an hour here adding shell membranes and mineral salts. After the isthmus comes the uterus, where the egg spends a whopping 21 hours adding the hard outer shell. This is also where the pigments are added and the egg develops its color.
As we found out earlier, egg color is genetic, and some hens lay white eggs while others lay brown. Perhaps you’ve noticed that brown eggs cost more at the grocery store? Well, there’s a reason why. White eggs don’t need to add pigment, which means one less step in the egg formation process. That also means less food requirements for the chickens and fewer expenses for the farmer. And fewer expenses results in cheaper eggs.
Egg color and chicken diets
Contrary to popular belief, chickens are omnivorous, meaning they naturally eat both plants and animals in their diet. This also means that all of the marketing about chickens eating a 100% vegetarian diet is just that – marketing. Larger egg companies will often use this technique as a marketing ploy to get people to buy more eggs. But buying eggs from chickens with omnivorous diets will give you a better-tasting egg, because that’s what their bodies are meant to eat.
As for the shell color, well, the chicken’s diet has little impact on the egg color itself. That’s just purely genetics. Typically, commercial egg farms will use proprietary breeds for mass production. These breeds were created specifically for laying large quantities of eggs in a short amount of time in order to turn the largest profit for the company.
White store-bought eggs
Most white eggs sold in stores come from Leghorn chickens, or a proprietary breed that originated from Leghorns. We see white eggs in stores the most because Leghorns are a big production breed. A single Leghorn chicken can produce up to 300 eggs per year, and begin producing eggs at 4 to 5 months of age. This also makes them the cheapest for a company to produce, and the cheapest for the consumer to buy.
Brown store-bought eggs
When it comes to the brown eggs found in stores, things can get a little more complicated. While most egg farms again use a proprietary breed, commercial brown eggs are typically produced by the Rhode Island Red. This breed is known for both its egg and meat production.
Another brown egg producer is the Golden Comet – a cross between the New Hampshire Red and White Plymouth Rock breeds. These eggs are also largely found in grocery stores. Interestingly enough, New Hampshire Reds are also descended from the original Rhode Island Red.
So, there you have it. Egg color is purely genetic and has nothing to do with the chicken’s diet or egg’s nutritional value. So next time you come across a blue egg, brown egg, or even an olive egg, you’ll have a better idea of what kind of chicken laid it.
Have you ever eaten an egg of a different color? Let us know!