Sounds normal to me from this and all the other information that you've provided. Thanks for answering the questions. It sounds like you have enough room for six chickens though adding some "clutter" in the run might help. It won't hurt as long as you can still operate in there without tripping. Take care of yourself too.
The best thing for her confidence is probably patience on your part. They are going through some personality changes as they go from not-laying to laying. I don't know where that pullet was in the pecking order before some started laying. She may have been at the bottom but it's quite likely she was at the top and is now being dethroned. You may see some other changes as the flock matures. Eventually they should settle down.
