You didn't mention how old they were so I'm assuming they are fairly young.
When daylight hours are shorter (fall winter in Northern Hemisphere) and/or when chickens are in molt the egg production slows or ceases. If they are not in molt you can add a light in the morning before sunrise so the total light hours (artificial and sunlight) equal to 14 hours. But it is best for them if they can have a break from laying for a few months. If they are in molt you will see them losing feathers and looking a little ragged. Nothing much you can do about that. If it's one or the other they will be back to laying in a few months.