I have a large hen that has been expressing some odd behavior within the past three days. She is kept in with 4 other chickens. 3 days ago, "Marge" was found laying down on the floor (in a nesting position) and wouldnt not get up even when food and other chickens were present. Apon moving her she would growl, grown, and cackle as if she was in pain. I noticed that she "bulked up" her feathers and spread them out. She would cower her head, try to peck at you, or try to cower in a corner. The feathers on her head are picked off to the point of raw flesh(no blood or scab) and when I finally did pick her up, some of the feathers underneith her belly and legs were missing. When I put her back down she remained in the "downed" state and would not get up on her own for 3 days total now. She recently laid a very soft, soggy, and moldy looking egg. She has had very few stool. Her appetite is decreasing as well. Her eyes and alertness appear normal though. I picked her up today and set her on her feet, she was moving around perfectly fine but cackling very loudly and unusual. Right now she is back in her original state, camped out on the floor of my barn. Is my chicken sick?