I noticed about a week ago one of my Sex link hens was not eating the special treats along with the rest of the flock. Over the past week she has eaten some but not normal. Now she stands with her neck kind of compressed into her body, her feathers are puffed up, and from time to time she will close her eyes. This is while she and the rest are free ranging. I picked her up and she definitely has lost weight, all feathers and bone. The crop feels empty and the vent looked clear of obstruction. She is almost 2 yrs. old. The rest of the girls seem normal. I have not seperated her from the rest but am thinking maybe I should. Anybody have an idea whats going on?