Last week saw two days that stayed below freezing, and water bottles froze for the first time this season.
Like sheep wool producers who are serious about the fineness of the fleeces their sheep produce, and the amount of fat on their bodies, I feed my herd to keep them on the lean side. They get barely 3/4 cup of the 16% protein feed mix I use. I keep the rabbits a lighter weight through the summer and fall, but when the temps start to dip down, I start changing my feeding routine.
It always amazes me how easy it is to overfeed rabbits, even while using a measuring scoop. So over time, I have come to appreciate the "mounding syndrome" inherent in my feeding style. I use a 1/3 cup measuring scoop for the summer and fall, and when the first frozen water bottle appears, I exchange it for a 1/2 cup scoop. This I feed twice a day, and using the "big scoop" theory, they then get about 1 1/3 cups of feed a day. This will add weight to their bodies in as little as two weeks. This extra weight will help them in the cold temps that are coming.
But, when serious cold weather moves in next month, not only will they get that extra feed, they get a Tablespoon of oats/flax seed at night on top of everything. More fat calories in the flax seed and extra warming carbs in the oats. They will burn it off to keep warm. And, they love it.