I think they know when they're about to lay an egg (unless they are new layers or laying soft shelled eggs). I usually do not let my girls free range till after 3 or 4 pm. I've been getting 10-12 eggs from my 13 girls for the past week or so. Today I let them free range at noon....only had 6 eggs in the nest boxes! I guess I'll be egg hunting in the morning:/(They have been living in the coop for almost a year now, and if they are kept confined to the coop and run, they always use the boxes and never lay one in the run...This nice spring weather had them not wanting to return to the coop before they had too!