One of my Black Sex Link hens of 3 1/2 months old was staggering yesterday evening and the other girls were picking on her. She suddenly rolled around on the ground and fluttered about like crazy. When I managed to pick her up, there was no heartbeat and her body was having spasms. In less than a minute, she died in my arms. Very thin and bony, jaundiced skin, comb and wattles dark and dry. I believe the yellow skin is a sign of a liver problem. This past week, she looked perfectly fine with no physical signs of health problems. I have 30 other hens, including four Black Sex Link, and so far no one else is showing any symptoms of health problems, combs and wattles look healthy and they are all strutting around. Has anyone else had this happen to their chickens? I have been watching stools and so far nothing looks unusual. Thanks for your advice.