They'll stop for many reasons. If you've had a spike in temperature lately, that could be the reason. Chickens are also creatures of habit and any changes can cause enough stress to stop laying. New flock mates, new neighbors, rearranging the coop, etc. Illness will also cause a drop/halt in egg production. Molting doesn't usually begin until autumn when the temperature begins to drop and have a more significant loss of daylight hours.