There are two main reasons why production slows down or stops at this time of year. First is the seasonal molting. While they molt, their bodies put all of their energy into growing in new feathers. Increasing the amount of protein will help get them through their molts faster. Some hens will start laying as soon as they finish their molt, others won't start laying again until spring is on the way.
The other reason is lack of daylight. The shorter days mean there isn't enough daylight for production.
The good news is that it's only about 4 more weeks till winter solstice and the days begin to lengthen again. Once the days are long enough, production should start back up.