Eggs galore...sometimes

Well, the girls are doing fabulously at the whole egg laying part of their day. All except for one strange thing....someone keeps laying an egg so that it falls down onto the ladder and breaks!  We are trying to diagnose the problem.  Erin...to herself quietly as she stares at the nesting boxes she has so carefully created for the hens....if i was a hen, what would I need to help me not lay my egg on ladder?  how would I need to be informed that the best place for an egg is in that soft cushy box??

All those pretty brown eggs!!