How old are they and how long have they been laying? How many were laying? Many pullets don’t molt their first fall/winter but keep on laying whether you extend the lights or not, though some do molt. Older hens molt and quit laying this time of year. Have you seen a lot of feathers blowing around?
Are they hiding a nest on you? That’s real common.
If it were just one I’d ask if she’s gone broody. They quit laying when they go broody but it’s unlikely all of them have.
Have you made any changes lately? Adding or taking away chickens, changing lighting schedule, moving them to a new coop or run, making changes to their coop or run can sometimes disrupt laying.
Is something getting the eggs? Many things that eat the eggs leave signs, but some things take the eggs and leave no clues. Possums, skunks, rats and the chickens themselves normally leave some clues behind thought he chickens might eat the shells. Usually they don’t eat the shells but occasionally they do. Canines, snakes, and humans take the eggs and leave no traces. Raccoons make carry the egg away but they normally eat them pretty close by. Has your family dog learned that the egg song is an invitation to a treat?