Dear Aggie

Question and Answer for April 13th:

Why do chickens lay colored eggs?

That’s a relevant question, as very soon many will attempt to color the perfect Easter egg! The egg dying process is fairly straight forward, but how do chickens lay colored eggs naturally? One word: genetics. According to Michigan State University Extension, the genetics of the hens laying the eggs will determine what pigmentation the eggs will possess. All eggs start out white (like many you would buy in the store), and non-white eggs get their pigmentation deposited in them from traveling in the chicken’s oviduct. This journey takes 26 hours from start to finish.

Also worth noting is that it takes 20 hours to complete the formation of an egg shell. The breed Ameraucana has the pigment oocyanin deposited on the egg during its journey through the oviduct. This special pigment permeates the egg shell and this turns the interior and exterior of the egg a blue color. Brown eggs come from the pigment protoporphyrin on the eggs during the latter part of forming the shell. Another breed is the Olive Egger. This breed has a brown pigment overlaid on a blue egg shell resulting in a green egg. The darker the brown pigment results a more olive colored egg (imagine trying to find that egg in the backyard!). Other than appearances there are no major differences between eggs of different breeds. A useful resource on this topic can be found at https://www.canr.msu.edu/news/why_are_chicken_eggs_different_colors.

Question answered by Jake Ledoux, Dairy and Livestock Educator with Cornell Cooperative Extension of Jefferson County. Contact him at 315-788-8450 or jtl224@cornell.edu. 

Last updated April 12, 2019