My one year old Buff Orpington has not laid an egg in a couple days. I'm not sure how long exactly since I just returned Thursday night from a 10 day trip. But yesterday she made a nest in the igloo I have in their run for weather/hawk protection, and she sat in there for a good hour, but no egg. This morning she was in the nest box and was in there for quite a while, but no egg. She is eating, not walking funny, her comb is rosy, and she seems normal in every way. Ideas?