At my grandpa's I gathered his eggs from troughs in his barn. He fooled his hens into laying their eggs there by having old white door knobs in the nests. lol
LOL! My Grandpa never tried the doorknob trick, as best as I can remember, although he was one that might have done it and I never knew it. They lived several hours from us and I only got to spend a few weeks every summer with Grandma and Grandpa.
I got me some plastic Easter eggs, put one in each laying box, they will move the around with their beaks to set on it lie OK, maybe a move This way will work. It DOES fool them and they will lay.