For some reason I am smiling here, because one next step is to see if they are going broody. I had a hen that literally disappeared over the fence for a week when she started laying ( I thought I had lost her to predators despite extensive searching for her). She had built a beautiful little ground nest with a dozen eggs in it...and she was completely hidden. I was super relieved because I had given up hope! Thought I had lost the little stinker and I had no idea what was going on...
Looking elsewhere for your eggs might be a good step. Where were they laying? In nest boxes always? New layers will look around for other nests, as protection. I originally found an egg here or there in flower beds while they were getting the hang of it.
I hung a pillowcase as a curtain (very stylish) over their nest boxes, kept the boxes clean and comfy, and put herbs like mint and lavender in there. Now that is the only place they lay (preferring one box to the other always).