Nutrena Nature Wise makes a "Feather Fixer" that is good for molting birds. I gave it to mine this year, and those birds that were not long into their molt when they started eating it did recover faster than the girls who had started molting earlier and were still eating layer food for the first half of their molt. Though light/weather was surely a factor, too.
@teaton , have you looked into Naked Necks for your DP birds? I keep mine just for eggs, which they lay plenty of (though maybe not as much as RIR), but I've heard people rave about the quality of their meat, especially the juiciness. Not sure if you have to have the Cou Nu/Poulet Rouge variety if you want to use them for meat, maybe someone with more experience in that department could weigh in on that. . . . But I have known them to have amazing temperaments, not to mention being very hardy and having fewer feathers.