I have 3 Red Star chickens all hatched on the same day. One the became of age one started laying first and then I was getting 2 eggs, one of which was very light in color while the other was a dark brown. Now for the last 3 weeks I been getting 2 eggs a day both dark brown. They all appear healthy and run to me for treats etc. One has a smaller comb than the other two but I haven't seen a lighter egg in some time. I do have a light in my coop. Any suggestions?