Good afternoon, We have about 40 chickens, which are about 9 months old. We've been keeping them indoors (about 200 sq. ft) since the snow fell, back in November. They receive some heat, at least enough to keep the water from freezing. Within the last few days, without any warning, one chicken died. We removed it from the others right away. This morning, another was not looking so good, so out she came. She has gotten worse and I'm afraid she'll die soon. No outward signs of sickness observed until they either die or have become extremely lethargic. They seem happy and normal one day and dead the next. I did check your FAQ's and the illness listings on your site. Nothing really describes our problem. Any ideas?