I have 8 week old chicks. I bought them from the same bin at Tractor supply. They were all sex links, and the sign says they were bred for egg production. 2 were brown, 2 yellow. The brown ones look and act just like I thought chickens would, but the yellow ones are ginormous and fat. They won't roost, I think they are too big! They can barely even climb into/out of the coop. They just las around all day. Is this normal? Was a mistake in the type of chicken made? They almost look like broilers to me, but I don't know much about chickens and this is my first time raising them.