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. Different eggshell colors come from pigments deposited onto the shell as the egg forms in the hen’s oviduct.
Chicken Breeds and Their Normal Egg Color
Brahmas: Light to dark brown
Jersey Giants: Brown to dark brown
Langshans: Very dark brown
New Hampshires: Brown
Plymouth Rocks: Brown to light brown
Rhode Island Whites: Brown to dark brown
Wyandottes: Light to rich brown
Cholesterol Content Versus Egg Shell Color
The blue-green eggs of the Araucana chicken have been items of interest for several reasons. They are unusual because of the color and the breed has sometimes been called the “Easter Egg” chicken because of the pre-colored eggs. The Araucana is not a new breed in the United States The origin of the breed has been traced to the country of Chile and the birds were brought to the America around 1920.
Another reason for attention is that Araucana eggs contain little or no cholesterol. Research results indicate that the color of the shell has no influence on cholesterol content. The research work compared eggs from the Leghorn and Plymouth Rock breeds with the Araucana. The results showed that it can be determined that in fact the Araucana eggs contained the highest level of cholesterol of the three breeds checked. Further tests compared eggs from different areas of the United States and results of these tests indicate that there is some variation in eggs, but that the difference is not of practical value. An egg is an egg no matter what color the shell, is perhaps a good way to answer questions concerning cholesterol from the Araucana. Although differences do exist, from a practical standpoint the differences are not of a significant magnitude.
Background information provided by Department of Animal Science Oklahoma State University.