I was given 4 barred rocks from someone that didn't want them any more during the spring. Ever since then I have noticed one very fragile/thin shelled egg or a broken egg in the nest boxes fairly regularly. About a week ago, I noticed one of the barred rocks started to isolate herself from the rest of the other 15. I couldn't understand why she was doing this as she had no other symptoms besides some occasional diarrhea. I thought she may have been worked up about two new roosters that were introduced two weeks prior, however about 5 days after her beginning to isolate herself, she didn't go into her coop at night and luckily I found her as it dropped from 60 to freezing within a few hours. When I brought her in she basically fell over as she couldn't stand well and seemed unbalanced. I had some extra 30% protein game bird crumble that was medicated and she started pecking at it after I had a brooder lamp on her. I gave her electrolytes and Corid in her water just in case. Her diarrhea has changed from foamy yellow to green and to white, and is very projectile over a course of a week. I always thought she was on the pudgy side, so I tied that and the mystery broken/fragile eggs to her and possible egg yolk peritonitis. However she is losing a lot of feathers, even including a couple primary wing feathers. I have been feeding her little slivers of apple, tomatoe, and grapes and she eagerly eats it, although it still isn't exaxtly normal amounts. She is drinking about a quart of water a day which seems excessive unless a lot is evaporating from the brooder lamp. She has made some progress and eagerly stands with much better balance when I go to check on her. I am debating on starting her on an off brand duramycin, it's the only thing I can find in stock locally, two stores were sold out, probably not a good sign... Any help or ideas would be greatly appreciated! It also seems that her belly and between her legs are a little spongey. Its hard to examine her as her feathers are very loose and falling out though so this may be misinformation. No other flock members are showing any differences in normal behavior even though temperatures have drastically fluctuated here. Could this simply be an extremely harsh/high stress moult or is there definitely something bateria related? I don't think it is worms, mites, or a virus as the others are still little bug chasing machines. Any ideas or past experiences will help!