I have recently lost three chickens suddenly and have no idea why. All were the same age 1 1/2 years old. Mixed breeds. All eat flock raiser. First hen was fine the night before, no signs of any problems. In the morning I found her on the floor in a corner. Her neck was very limp and she was barely alive. She died within 5 minutes. Second hen was in another coop. She was ok in the morning, but had died a few hours later when I checked on them. She had not been laying and not acting quite right for a few weeks. She had also been jumped on by a young rooster a week prior, so her death may not be related. Today my lead rooster in the same coop as the first hen died. He was fine last night. He came out of the coop as usual, then stumbled slightly. He stumbled a few more times until he fell on the ground. I picked him up and he pretty much died the same as the first hen, but very quickly - less than a minute. He had a bad case of pox this summer. It was inside his mouth and he was very sick. I still have the rooster and could have him checked, but have no idea how to do that.