I have a 6 week old RIR who appears to be sick. She is feathered out and won't stand up. She has a good appetite and will drink.. Her poop appears to be normal. Where do I begin to research what could be wrong? This is my first time raising chickens, we purchased 5 dibs, the other 4 appear to be normal. I have isolated the RRI from the others so they would not harm or bother her.