Just wondering....I have a Barred Rock hen about 5 years old that has been very docile and quiet lately. She just seems "off" and I am not sure why. When I feed the rest of the flock she stays to herself and does not go after the food like the others. Her hind end looks as if she has some green diarrhea. All other hens (12) are acting fine. Any ideas what to do for her or what to look out for?