ok..this it what you do...tell them this in the morning! "Lay some eggs or i'll eat your legs!" I said that to mine and the next day my first egg! are they doing the "hen squat"?
My 4 are going on 21 weeks and two have started laying. I would say in the next few weeks they will start. I know it is difficult waiting though. It will be so worth it though after you get through the small pullet eggs.