We lost one of our three hens last night. No warning signs that we noticed. She was hanging out with the other two like normal all day yesterday. This morning she was dead in the coop. No signs of illness or injury. She wasn't a friendly bird at all but she was pretty. She wasn't quite three years old. She was one of my mystery birds, a small gray hen that we got as a pullet from the local agricultural university's flock. We'll miss you Dove!