Nesting boxes help
I don't think they are supposed to have gaps in the slats in the bottom of your nesting box .... not sure what could crawl through a 1/4" though. It was probably made that way to keep the weight down and cost effective. I would cover it with a sheet of tin and then cover that with linoleum. Then, I would add some nesting material so the eggs don't roll and get broken. Once in a while our hens move their eggs around.