Usually my chickens are anxiously waiting for me to let them out of their coop in the morning, but today one of my girls, Rosie, didn't come out of the hen house. She was still roosted up top and didn't seem to want to come out. After a few minutes, she went down into a nest box where she has been ever since. It's been about 2 1/2 hours. She has her eyes closed and isn't sitting in there the way she normally does. I am concerned because she is normally the most outgoing in my flock, she is usually very vocal and active and just isn't herself. They are all usually very excited to eat in the morning and come running out of the coop. She hasn't had and food or water yet. All of the other chickens are acting normally and Rosie was too yesterday. Does anyone have any advice or have you encountered this before? I realize my worries may be premature, but this is very weird behavior for her. She is a Buff Orpington, about three years old, and laid a beautiful, healthy egg just yesterday.