I have two hybrids, now 18 months old, and one of them, a Leghorn hybrid, stopped laying and moulted in October/ November, having been in continuous lay since the previous October. She's just returned to lay in the last few days. The other one, a Columbian Blacktial, the same age, has gone on laying a daily egg since last October, a straight 14 months with no break, and shows no sign of stopping or moulting yet. My two 2.5-year-old purebreds have moulted this Autumn and still no sign of their return to lay. So its possible that yours may not even moult this winter, and it seems unnecessary to worry about it unless or until it does happen.
I would guess that it's partly to do with their breeding, with hybrid layers less inclined to moult at all in the winter after the year they were hatched, as this would be convenient for a farmer hoping for continuous egg production through the winter months. For purebreds, a moult at around 18 months would be more normal. And also, as Foxy suggests, on their age - in my limited experience, pullets don't moult in the Autumn/Winter of the year they were hatched, having moulted and re grown their feathers at around 14 weeks of age when they get their adult plumage.
I would continue with their normal layers diet, and ensure they have dry, wind proof shelter if they need it, whether in moult or not. If you give them a warm mash, do this in the late afternoon so they go to roost with full crops to last them through the long cold 15+ hour-long nights.
