This past spring, we had two chicks hatch from nice blue/green eggs. The hens are Easter-eggers, obviously not pure bred. They have the puffy cheeks. Anyway, the chicks finally started laying eggs in November. One egg was a deeper brown,the other egg was light tan/cream. We were confused as we thought since they came from green eggs,and our rooster is also an Ameraucana, they would lay green eggs too. Anyway, after about a week, one day the lighter colored egg was like an olivey green color and now it is a light green. The dark egg is still dark. Strange, but true!