I have 6 chickens and all but one have started laying. All but one are laying during the day. I have one chicken laying sometime during the night and laying from the perch. This morning I went out and found an egg broken but the yolk was still intact. I put the egg in a bowl to get rid of inside. When I put it in the sink i could not brake the yolk. I had to cut it with a knife. The membrane was so thick that it looks like plastic. Do you think something is wrong with her or do you think it's because she is young and dark in there that she doesn't want to go to the nest box? What would make the membrane like that? The shell was separate from the inside of the egg. I basically just picked up the inside of the egg and put it in a cup. It was like the yolk had another membrane around it.