It might be difficult to do but, the hens really need layer feed. It is balanced for their needs. You will probably get posts from others about the pros and cons of using a medicated feed.
The biggest thing to slow down production and possibly stop it all together is light and temperature. Is your coop lighted for 12-14 hours a day? It is also not a bad thing for them to take a break from laying. Let their bodies build up again. I feed all my birds a mixture of gamebird feed, (higher in protein), and layer feed. It has increased egg production, and keeps their bodies from getting to stressed in cold weather. I think a developer feed can be used that is not medicated and would be better for all the birds.
MsBear, has some good posts about winter egg laying. Do a search and see if any of the info helps!
Good luck.