I have 4 chickens. I free range them during the day and coop them at night. 3 of the 4 come back on their own, but one seems to have trouble getting back in the coop. She gets to the coop, but it seems like she can't figure out how to go inside. The door is open right in front of her. Each time we've had to catch her and put her in ourselves (chickens are not easy to catch). Is there something wrong with this chicken or will she go in when she's ready?