I did some research and found that there are a few reasons hens will peck at eachother. Like you said, it can be because they are figuring out who is where on the totem pole. They have been together since pullets, so I don't know about this. But maybe they will just pick on the bottom hen as long as they are together. This same hen has had a scabby comb before, so it isn't totally new behavior. Also, they can lack protein or vitamins, or if they get too much light. I'm pretty sure they get enough protein because they get a lot of meat table scraps, but I have had the light on all night and day in their coop due to the cold weather. So I am going to start turning the light off at night and hope they don't suffer. Also, I might try putting vinagar in their water to see if that helps. Thanks!