Has anyone else encountered avian infectious hepatitis? I lost a hen to it a couple of days ago. I'm new to chickens; I've had four for only 3 years. About a year ago, one of my hens stopped laying. I contacted the local cooperative extension, which advised me that she was probably either at the end of her laying years or reacting to a series of stresses, and that it wasn't anything to worry about. At the same time, her behavior seemed to change. She became less aggressive and less assertive and adventurous. At the time, I thought it was a reflection of a change in the pecking order. About a week ago, she became less interested in food. On Saturday, she was noticeably less active. The next day, she didn't come down from the roost. When I picked her up, I could see that she was very thin and her shanks and feet were darker in color, less yellow. She was extremely weak and wouldn't eat. I was treating her for everything possible but she died the next day. I had no idea what was wrong so I convinced a local vet to perform a necropsy. He said she died from acute hepatitis, probably avian infectious hepatitis. She was 100% involved by then and could not have recovered. The time to treat her was of course last year. Apparently, the first symptoms of hepatitis is that they stop laying and withdraw. It is treated with terramycin, for two weeks, which I am now giving the rest of the flock. The change in color of her feet was a symptom of advanced liver disease. The vet told me that she could have been carrying the illness from the time she hatched and that some chickens are immune. Is this common?