I have 12 nice nest boxes. They lay in three, and also lay in the corner of the room. Oh well. Whatever makes them happy, right? At least they are laying in the house, and not under it!
For a while, my chickens all started laying under the chicken coop! What a mess!
I have a stone egg that I put where I want the girls to lay and some of them will lay there. They seem to be saying, " Oh, look, someone laid an egg there. Must be a good egg laying spot!" Talk about peer pressure!
Except of course my one hen who lays right in the feed bin!
I don't think it is really anything to worry about. But, if you want to, I would plant some real eggs in the places you would like them to lay and leave them there for a few days.
Good Luck!