When I bought her as a chick, not knowing how old she was but she was very small. I figure about 2-4 wks old. She got FAT really fast along with my roo, both Rocks. He started acting really funny. Started turning his head almost all the way a round. I started watching him and decided that he must be blind in one eye and was twisting to be able to see. Now I am just not sure. He was fine at first but I had 4 newbys in the same cage, all bought at the same time, until I could get my henhouse done. When I put them in the coop, about 6 wks later, they started growing very fast. The Rocks got really big, really fast. I noticed that when he started twisting his neck as he did that he was also losing feathers on his underside. Eventually he died. Now My hen doesnt twist her neck like he did but she is losing feathers on her underside just as he did and she gained weight just as fast as he did. She seems to be gasping for air all the time. She is very overweight. The rest of my birds that I bought at the same time seem to be fine. I have given them the Di-methox in their water and she seems to be a little better today, however, I think there is more going on with her. I have not raised chickens in the past 20 yrs and I have never had these problems. All that I have ever raised have been so easy to take care of, disease free. Any suggestions?