Getting the Bluey-Greens … and Browns!

In Chickens on July 5, 2008 at 1:56 pm

Our fresh farm eggs are available during the week at McCusker’s Market in Shelburne Falls.  When you open a box of our farm eggs, you will see both bluey-green eggs, and brown eggs.  The colored eggs are layed by a different breed of chicken than the breed that lays the brown eggs. They are equally fresh and tasty.

A couple of years ago, the Ask Dr. Knowledge column at The Boston Globe published an interesting piece on the difference in chicken egg shell colors. Ask Dr. Knowledge is written by physicists Stephen Reucroft and John Swain, both of Northeastern University.

They reported the following:

  • Eggs have shells that are mainly (about 95 percent) composed of calcium carbonate — a white substance that you have no doubt also seen as chalk or limestone. There are additional chemicals that can affect color.
  • The breed of chicken determines what color the eggs are, so it’s a question of genetics. In a way, it’s not so different from what determines the different colors that peoples’ eyes or hair can be, even though they are all people.
  • Brown egg shells get their color from a substance called protoporphyrin that comes from the breakdown of hemoglobin in blood. This pigment is deposited on the surface of an otherwise white egg as the egg is formed and can be rubbed off with sandpaper or dissolved off with vinegar — something you can easily verify at home. Blue and green colors come from a pigment called oocyanin that is produced in birds along with bile. As you point out, there are actually chickens (Araucana chickens) that lay blue-green eggs. They are sometimes called “Easter Egg” chickens since their eggs are precolored.
  • Assuming that the chickens are well fed and healthy, there is no particular reason to expect that one or another color egg is more or less healthy. Rumors that Auracana chicken eggs are lower in cholesterol have not been supported by tests.

* * * * *
For some more interesting information about the complex chemical scramble that make up eggs, you can visit here.

You can purchase Wells Tavern Farm eggs for $3 a dozen and  $4.50 for 18 at our farm — or enjoy our newfound convenient location at McCusker’s in Shelburne Falls.

  1. Hello there,

    Good egg info. I’m actually writing my farm newsletter at the moment and wondered if you would mind if I sent them to your blog. I’m planning on sharing some of the info in this post and would like to give credit where credit is due.

    Can I tell them you’ll be happy to have them checking out your blog? (There are only 50 subscribers).


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