Came out today to find one of our chickens had been killed by the others. She was laying outside with all the feathers missing from her neck and blood spread around the coop. I have no idea why this would have happened so I am hoping someone else has an idea. Some Background: We live in Montana where there has been snow on the ground consistently for the last two months. We have (had) 7 chickens all raised together from chicks and about 10 months old. 2 Reds, 2 Silver Lace Wyandottes, 2 Spotted Sussex, and 1 Blue Andalusian. The Andalusian was the one that got killed. She always seemed like the top hen. The chickens just seem genuinely unhappy and cooped up. They haven't been venturing into their outside run much with the snow and they mostly just hang out inside the 8x5 coop. They love getting to free roam outside the pen but we haven't been able to do that with it getting dark so early. I'm not really sure what to do for them. I give them a head of lettuce every few days which makes them happy for the few minutes it takes for them to eat it. Any ideas to help them get through the winter months without killing each other appreciated.