My 6 month old BO roo just laid down in the yard today and died. No sign of injury. No symptoms of any disease. All the other chickens are fine. He had been eating, crowing, mating, and had lots of energy just an hour or so before. Has access to plenty of shelter from the heat, water, and food. He didn't even flop. He laid down on his belly and just died; his feathers were all in perfect place. Have you ever had a chicken just up and die for no apparent reason? I guess that's possible, but it's still puzzling.