Were they recently really scared by something? That will cause a back-down in production. But its probably the season.
I've learned so much from my hens. I used to think they started their production back up in spring, and quit in winter. But what they respond to is the length of the day. That means they might start to decline their production after June 21 (summer solstice) and pick up on it after December 21 (winter solstice). They know when the time is right to maximize the chances of survival for their babies. (should their eggs be fertile). My hens are getting old, and they're drop-off seems to get earlier and earlier.
Some people put artificial lighting in their coops to "fool mother nature" in order to keep egg production up, but I like to give the girls a nice break in the winter.