We allow our laying hens to free range outside their run in the late afternoon/evening. Some of them have gone missing with no evidence as to what's happened to them--until this week when our neighbor told us he saw a Great Horned Owl carrying one of my hens away! Two days later we found this feather laying outside the coop. It's about 12 inches long and comes from a very large bird. I'm just guessing that it was left by something that is after my hens, since we don't have any other large birds that visit. Any ideas what kind of bird left this feather? Is is a bird of prey? Any ideas about how to discourage them?