I noticed one of my chickens was not moving or eating. She was just standing huddling but with her eyes wide open. This has been going on for a while. I noticed she had a lot of poop caked around her vent. I removed it, separated her from the flock. But she is still not moving around very well and she is not herself. One of the other chickens already died from whatever this is, I do not want them all to. Any suggestions as to what it is?