My flock of 7 has always roosted together from when then were fuzzy chicks piled on top of each other to now (a little over 6 months old). There are 3 roosts in my coop and they all roost on the top one. At first they all roosted on the middle one and then when one figured out how to go up, they all did. For the last 3 nights, one of my Wyandottes has been roosting on the middle one by herself. When I went in to lock up the first time she did this, I checked her out, she seemed fine so I put her on the top roost myself and she seemed happy enough to stay there. But the next 2 nights it was the same thing with her roosting on the middle one alone. No other behavior changes and she doesn't have any obvious physical problems and she's laying almost daily. Is she just sick of roosting with them or should I be looking for something wrong?