A few months ago (mid July) I noticed that one of my 4-year old Black Australorp hens was loosing weight. Since it was pretty old, I just determined it was old age. However, a few weeks after, it's comb began to shrink but not loose color. I also noticed that poop was building up around it's butt, and it had a very strange smell. I immediately started trying to determine what disease it could be, but multiple internet searches of common diseases resulted in nothing. So I brought it in, cleaned it up, and tried feeding it. It had no issues eating food but it continued to get weak and have trouble walking. It died soon after. I cleaned up the coop and treated the rest of the flock with some Vet Rx. Well, this past week, I lost another 4-year old hen to similar symptoms, only this one seemed to be gaining weight rather than loosing it. It also didn't seem to get weak, it just died today. Other than strange-smelling poop and a shrinking comb this one seemed to be healthy. (very perky and had an appetite). So now I need help with this. Tomorrow I'm going to do a deep-cleaning and disinfection of the coop, but is this some serious rare disease that I have never heard of? I have only 5 hens left, one is 4 years old, one 3, and 3 2 year old hens and I really don't want to loose anymore. Did the 2 hens die from natural causes or is this a disease that I can treat?