One of our hens has something wrong with her and thought someone here may have some idea what is going on. She is about 8 months old and a few days ago we found her sat out in our chicken run acting like she cannot hold her head up/straighten her neck. She seems to want to hold her neck curved like a hook when she is not moving. She is able to move her head around but seems to lack control. A lot of the time she will just sit down and tuck her head back into her body like she is sleeping. We can get her to drink but not eat. We do have her isolated from the other hens. None of them are showing any signs of the same thing. She is not showing any sign of improvement. Any thoughts?