No reason to feed layer (which is primarily mixed for the higher calcium, among other things) while they're not laying. And, in my book anyway, the argument that added carbs will contribute warmth (not just from the exertion of the gut in digesting it) is a sound one.
But if the birds are in a molt, I'd focus on upping their protein while they're molting, from they 16% of a typical layer feed, to a starter /grower of 20-22%. Feathers are large part protein. The more you can give them, the faster they'll feather back in without sapping much if any of the proteins in their own systems. If you're in an area with remarkable cold, it would be important to feed them so they can do that quickly.
If you have some that are laying sporadically, just keep some oyster shell where they will find it to replace what thay aren't getting from a non-layer-type feed.