My parents are dealing with a chicken that seems to be ill, and I thought you might have some insight. She has been staying on the coop floor tucking her head under her wing. Dad moved her to the run hoping she would eat or drink. She drank some when they dipped her beak. She won't eat food or grass. They've separated her and given her food and water. She doesn't have a pasted bottom or anything obviously physically wrong, so I'm at a loss. She is a ten month old Barred Plymoth Rock. The only difference to her routine has been colder temps, but she was in a cozy coop with 6 other hens. Any thoughts? Anything we can do for her?