Most of my girls seem to prefer the "bare" approach as well; others like bedding in the boxes. It certainly keeps them busy...one climbs in and busily scratches it all out. The next one very carefully redecorates, LOL. In order to make sure there's something in there to support the egg, we put a piece of "welcome mat" in the bottom; the kind that has little plastic bristles on it. Seems to give them a texture they like and they can scratch at it with no harm. When it gets icky, we take it out and hose it off.
Four of them don't seem to like the boxes and lay on the floor. They all scratch all the bedding away and lay right on the floor. To provide a bit of protection for the eggs, we put down some corrugated plastic...looks much like cardboard but is sturdier. They scratch and peck at it but it's still smooth and is a bit more forgiving than bare wood.