Last week my 6 month old chickens started laying eggs. I have 1 barred rock and 1 RIR and 2 americana's. The dark brown ones are all the sane size and same color. I noticed that my rooster kept on joining the barred rock so I figured the dark brown eggs were hers. Then the other day I was home and the barred rock was making a lot of noise and a couple minutes later I check on her and she is sitting on the light brown egg. I had to move her out of the way to get and it was really warm like she just layed it. Today I got one dark brown egg and one light again just like the one I got from the barred rock. So I was wondering if my barred rock is laying two different colored eggs or is my RIR laying the dark brown eggs. I know it's not the americana's because they would be blue or green. Can some one plz explain this mind boggling theory to me? Thank you.