I have a hen that has been sitting in the hen house for a few days now and won't come out to free range. I took her out of the hen house yesterday and she drank water and ate some feed and then got back in the hen house. I am not sure if she has layed any eggs recently since all of the chickens tend to lay there eggs in that one nest but noticed that the other two hens have started using the nest beside her. We have 6 other chickens that are too young to lay now but will be laying shortly. Is there a common sickness that this hen may have or perhaps a disease that she may have developed? All she wants to do is sit on the nest with no eggs under her and puff her feathers out when I get near her.