I've got a chicken who will sleep in the nesting box if we let her. The nesting box that she uses is at floor level and both roosts are higher than the nesting box. She started doing this about a month ago after using the roosts like normal. If we push her out of the nesting box before it gets too dark she will usually jump onto the roost. If its too dark we have to put her up there and she'll stay most of the time. Occasionally another chicken will peck at her and she will jump down even though the pecking isn't that bad. She doesn't get bullied during the day. We've been putting her on the roost manually for about two weeks. The last thing I can think of to try is to block off the nesting box before they go to roost to get her back in the habit of going to the roost by herself. Any other suggestions?