My egg production seems mostly tied to temperature. If it's cold (like in the 20s or below) egg production goes way down since the chickens are tryin to keep wam. Upper 30s and things are mostly normal. You might try feeding a higher protein content feed in winter if you aren't already. My girls did ok last year on that 20% layer feed that ifa has.
I want to try alfalfa. Hearing that is good. Right now I am using Calf Manna as an extra protein. They love it, and it doesn't take much.