We have a 2 y/o Buff Orpington. All of a sudden she has stopped roosting and just sits on the coop floor. All other chickens are roosting on their perchecs. She seems lethargic at times but runs the yard on occasion. Is this something to be worried about? She keeps getting pooped on by the other chickens in the coop since she lays under them not on the perch with them!