I am a new chicken owner and have had my chickens for about 2 years. Recently one of my chickens became sick and she hasn't been eating or drinking that much. She has been eating a little bit of wet bread and a little water but not nearly as much as she used to. She doesn't move around or walk very much and just sits in place for hours. Her poop is coming out light green/whitish diarrhea and she is not laying eggs. Her feathers are coming out whenever you pick her up. Her mouth also remains open for a few seconds at a time when I see her (see pic). I don't know what's wrong with her and would appreciate any advice!