I was given 2 hens by a friend who did not want them anymore. I kept them apart from mine (good job I did as one developed respirator disease and died). The other one was really healthy and after 5 weeks I moved her into my main flock. Its now one month later and I was doing some work in the run, and I had to pick her up to move her out of my way. I was shocked to feel how think she was, I could feed her breast bone. All the other chickens are fat and healthy. She does not seem to be ill at all and is eating and pooping normally and is lively. If she had worms would that cause weight loss? She is not fluffed up or acting sick and her eyes are clear and bright.