I think the original question was how to acclimate fall-raised chicks to the bitter cold of winter. My answer is to brood your chicks, once you obtain them, outdoors under the MHP system. If your coop, like mine, isn't large enough to fix up a pen for the chicks, and the run is enclosed and weather-proof, you can brood right out in your run.
Read up on the MHP system of brooding on this forum under the thread entitled "Mama Heating Pad in the Brooder".
This year for the first time I brooded two batches of chicks outdoors in my run in a secure pen under this system. The chicks go out right from the start, and their only source of heat is a tent made from a wire frame and a heating pad (the kind that won't shut off after two hours). Of course, you will need electricity to your run for this. They warm up under the heating pad and spend the rest of their time having a grand time racing around a nice spacious area with the rest of the flock communicating to the chicks from the rest of the run.
As the chicks feather out, they spend less and less time under the heating pad, and usually feather out very quickly due to be exposed to natural outdoor temps. In fact, it makes no difference at all how cold it gets. This system will keep the chicks warm in any temperatures, even minus freezing.
There is no downside to this system that I've been able to discover after using it twice now. But the benefits are many. The chicks are accepted as flock members from the start and it makes integration a breeze. Mine were mingling with the adult flock at three weeks and roosting in the coop at five weeks with no additional heat. They will be very cold hardy from then on.