We got our first egg yesterday (yahooooo!!!!!) but we have no idea which chicken laid it. We got another egg this afternoon and, again, don't know who laid it. It's roughly the same size as the first egg but is noticeably darker. What do you think-are two chickens laying or just one? Is there this much variation usually? If it helps, the 4 chickens are a Delaware, Australorp, Dominique, and RIR. Everyone is 21 weeks and a few days old.