I feed my (6, 4 embdens and 2 toulouse) just a small handful of whole wheat each day, through snow, hail whatever and they seem to come through the winter very well. Im assuming they are keepers, not being fattened so it is just a maintenance ration.
Im not sure about the recommended stocking level - even tho in NE Scot we still have grass for them as the 6 have about an acre to themselves. Not sure I would have 25 on 2 acres up here as our grass season is short.