I am an 11-year-old owner of five backyard chickens. This morning when I let them out of their coop to free range, one was very listless. She sat right outside the door with her eyes closed. I examined her and noticed her eyelids were droopy and puffy and her skin around them is pale. I put her in her own box in the garage with food and water. Does anyone know what might be wrong with her? She is a Plymouth Barred Rock hen, age 16 weeks. There is no blood in her poop. The other hens seem fine. I did not notice anything was wrong with her yesterday. Her name is Betty Lou and she is my very favorite. She likes to sit on my shoulder and go in our climbing tree with me. pleas help.