(From http://bloggingerika.hubpages.com)

Have you ever wondered why some chicken eggs are green or blue or pink or brown? Do pink eggs come from lightly colored red chickens? Does chocolate milk come from brown cows? Actually … NO! Gretchen Anderson, author of The Backyard Chicken Fight (Mill Park Publishing/2011), states that, “The egg shell colors run the spectrum from white to dark brown (as dark as a Hershey chocolate bar).  And, there are the chickens (Ameraucanas and Araucanas) that are the so-called “Easter Egg-er” chickens because they lay green, blue and pink eggs. The eggs all taste the same despite the different color shells.” And then there are those that say that the color of the ear lobe determines egg color. Chickens have ear lobes? I didn’t know that. “If you carefully push back the feathers on the sides of a hen’s head, you will see the hen’s ears. White ears correspond to white eggs. Reddish brown ears correspond with brown eggs. This correlation supposedly holds up for light green and bluish eggs, as well”, says Shirley Corriher (internationally renowned culinary expert) writes in her book CookWise.

Really? Most of the sources that I came across, said that the color of the chicken feathers or skin or ear lobes may have some correlation with eggshell color but they do not determine color. OK. So where does the color come from, then? The biological answer from Yahoo Answers, Backyardchickens.com and Wisegeek, among others, all agree that, “It’s all about genetics. Eggshell color is in genes inherited from the chicken’s parents. Egg shell color ranges from white, cream, pink, brown, blue, green to even dark brown chocolate colored. It has to do with pigments called porphyrins that are deposited along the hen’s reproductive system as the egg passes along the tract and the shell forms. Different porphyrins cause different shell colors. For example, brown eggs are the result of the pigment protoporphyrin. Auracauna chickens lay green eggs becuase they posses the pigment oocyanin, which causes the green/blue eggs.”

Barbara Joan Myhre, the Chicken Lady, agrees with this statement when she says, “Thus sayeth the chicken lady: The Aruacana is is the breed which lays the colored eggs. Usually, we get blue, green or blue/green ones, but occasionally get pink ones. We were always told that the earlobe color is indicative of the egg color. However, Aruacanas have no earlobes. They have lovely feathers which look like outward facing sideburns. If they have earlobes, we’ve not seen them. We also have some precious varieties, with great feather patterns. Silkies, have lovely, soft feathers.” And Victoria Williams adds to this when she says, “Well supposedly color of ear lobes….and breed, of course.  Our Barred Plymouth Rock (Tootsie) lays the proper light brown colored egg she’s supposed to, as does our Silver Laced Wyandotte, Jelly Bean.   Our Araucana, or Easter Egger, Ginger, on the other hand, is supposed to be laying blue or green eggs but all we get from her is light brown which also may be considered pink.  We’re planning on adding to our flock next spring and I’d love to find a couple of French Maran chickens which lay dark chocolate colored eggs.” Can you tell all of these folk love to work with their chickens?

Which finally leads us to the last question: Which specific breeds of chickens lay the most varied colored eggs? “White eggs = the ancestors of chickens that lay these originated in the Mediterranean. One of the most Ancient breeds is the Dorking that came from Rome during the time of the Roman empire.
Brown eggs = the ancestors of chickens that lay these came from Asia, primarily China. The Cochin is a very old breed from China.
Blue eggs = the ancestors of chickens that lay these came from South America. The Araucana is best known for laying blue eggs. A true Araucana is rumpless, having no tail at all (not even the fleshy part). A modern breed that lays blue eggs is the Ameraucana which does have a tail. All other egg colors come from blended genetics. For example, breed an Ameraucana (blue eggs) to a White Rock (brown eggs) and the pullets will usually lay greenish eggs.” (Backyardchickens.com)

Interesting information! From the evidence that I have read, the color of a chicken eggs is determined by genetics and that the color of the feathers or ear lobes may have a correlation to the egg colors. Specific breeds of chickens may also lay different colors of eggs. Further investigation and reading will reveal that there are three main colors for chicken eggs. Most eggs in the store come in white or shades of brown. It is also possible to find blue to green chicken eggs which come from the Aracuana, a breed of chicken developed in Chile. Araucanas have also been crossed with other breeds to produce the Americauna, sometimes called the “Easter Egg” chicken in a reference to its multicolored eggs.

I must thank Gretchen Anderson, author of Backyard Chicken Fight (Mill Park Publishing/2011), Barbara Joan Myhre, the Chicken Lady and Victoria Williams, backyard chicken raiser, for the information they provided for this post. Other sources include Yahoo Answers, Backyardchickens.com, Funtrivia, Wisegeek, Murry McMurry Hatchery in Webster City, Iowa and Backyard Poultry Magazine, March 12, 2012 article “Ameraucanas” by John W Blehm, Pres Ameraucana Breeders Club.