Lots of well ventilated space in the coop, especially if you don't have a good sized weather protected run.
Tell us how many birds and what sized coop(with pics) and we can help you prepare.
A heated waterer, unless you want to tote thawed water multiple times a day.
I love my heated waterer with horizontal nipples, for both no spills, no evaporation, and best for heated waterers. But need to train them to nipples before winter sets in.
I keep a path shoveled in my run, for easy access to clear snow off roof when needed and room for them to move....also speeds snow melt in run during thaws and spring.
I toss down a thin layer of straw or shavings when icy or to lure them out. Some like to walk on the snow others stay in the small shelter area under the coop...where the dirt stays dry and thus unfrozen for all year dust bathing.

It's funny, but annoying too, many wattles with mild to severe frostbite from snow bank noshing. SMH.
Tell us how many birds and what sized coop(with pics) and we can help you prepare.
A heated waterer, unless you want to tote thawed water multiple times a day.
I love my heated waterer with horizontal nipples, for both no spills, no evaporation, and best for heated waterers. But need to train them to nipples before winter sets in.
I keep a path shoveled in my run, for easy access to clear snow off roof when needed and room for them to move....also speeds snow melt in run during thaws and spring.
I toss down a thin layer of straw or shavings when icy or to lure them out. Some like to walk on the snow others stay in the small shelter area under the coop...where the dirt stays dry and thus unfrozen for all year dust bathing.
Freezing temps and humidity or 'wet' skin.So they only get frost bite when its below freezing, Right?
Well, not mine, they eat snow despite fresh warm water always available. I wish I could have captured a pic of the snow banks with peck marks all down it at beak height.They do eat snow but mostly when thawed water is scarce.

It's funny, but annoying too, many wattles with mild to severe frostbite from snow bank noshing. SMH.