They have a mind of their own. Straw is much better and easy to clean. They poop everywhere already so keeping a clean pen is a full time job. Just gotta roll with it. The trays might have something to do with them NOT going there to lay. They will decide where they want to go but you might want to consider a wooden box. I have 4 layers and they all use the same box. Drove me nuts at first cause I wanted them all to have their own, however, they decided for themselves. I never have poop on my eggs as my hens do NOT poop in their laying box. I have 6 laying boxes and they all choose the same one to lay in, the other have poop. I keep a lot of straw in the boxes to make it easier to clean. I doubt that fake eggs will make them lay any differently than what they decide for themselves but my Grandmother used to use them to make the hen brood in the Springtime. Thinking about trying that one this coming Spring. Consider that they are on a schedule and when they form that schedule, you will know it. They are like women, just can't predict what they are gonna do, however, you can watch them a figure them out and their schedules will fall right with them if you are feeding them laying mash and feeding them on schedule.