wintering chickens:
Bag balm (green tin with clovers on it) if you did get single comb varieties. Vaseline is worthless. Hens will tuck their heads under their wings to keep warm, though, And I think GFTG's roo is an EE. So no comb issues there.
Low roosts. Broken toes and feet freeze and fall off. Broad sides of 2 x 4s so they can enclose those feet in their feathers when the feet are cold. Inside the coop and put one out in the run too. Consider straw for a flooring base. The straw makes for a warmer floor because the airspace in the shaft of the straw stem is an insulator. Personally I don't like the poopy feet that I get with straw. So I double up on pine shavings but I know it's not as warm. Sand is less warm again but the cleanliness factor is unmatched.
Watch them on days that are rain/ snow mix days. (High humidity) And of course -25 to -50 F weeks in a row is tough on them.
No hot steamy oatmeal or squashes to warm them up on cold days. You'll steam freeze the wattles right off them.
I have been known to put warm tap water in the waterer on the nasty mornings though.
Greens. Buy a bag of kale at
Walmart. It's $2. Or spinach. Handful each day as a treat with scratch. Or go get the past prime stuff from your grocery stores produce section. They'll probably give it to you for free. Kitchen scraps. Whatever.
They really crave the greens in the winter.
Grit. Get a couple bags. If snow is covering access to gravel in your driveway or wherever they'll need that to process their food.
Dusting bin. Again they'll want to groom themselves with a dust bath now and again. Scoop some sand and wood ashes into a larger pit or I used a galvanized wash tub.
Do checks for lice/ mites every month. Being on hay or straw or just those things finding a warm home before winter hits is always a possibility.
That's all I can think of in addition to ejb's and Minnie's posts for winter. Last winter wasn't bad but the two before were rough. 6 solid months in the run. Sit on a designated bale in the run in your carharts and enjoy them. You feel sorry for them and they're bored and grumpy and you never look forward to spring so much until you have chickens.