Last year was my first winter as a chicken owner in Vermont and it went very well. Here is what I did:
First off, here is an intro to my set-up. My chicken house is home to 6 girls and is about 5wx5dx7h. It sits on stilts so that the floor is about 1 foot above the ground and the floor is hardware cloth with a thick layer of straw over it. When I originally made the house, I insulated it with some bubble wrap/foil-type stuff I got at Home Depot. It's only about 1/4" thick and easy to tack up--I put luonn over it so it wouldn't be pecked and plucked at, plus it looks nicer and works better if it is trapped between two layers. The ceiling has a layer of 3/4" foam board insulation under luonn.
I almost put a layer of plywood over the hardware cloth but then decided not to. I'm glad I didn't because it allowed for good air circulation in there. There are two windows in the house, both of which are just hardware cloth during the warmer months. I almost made plexiglass windows to install over the hardware cloth, but again, I'm glad I didn't. Instead, I stapled heavy gauge plastic over the openings. I think windows would have made the house too tight, causing health problems with the chickens.
I suspended a heat lamp inside the house from a corner and ran an extension cord into the garage, which is about 10 feet away, then put that on a timer (this year, my husband ran electricity out there for both the light as well as my electric fence). I set the timer so that they would have 12 hours of light/day. To help keep some warmth in the house after the light went off, I made sure to close the door at least an hour before lights out, and once I pulled up the electric fence--when the snow got too deep for it to work anymore--I was shutting the door at sunset.
I also fed my girls some cracked corn just before I shut the door. I read that if you give them protein just before bedtime it helps them to stay warm. I knew that they hunker down over their tootsies, so I wasn't worried about that.
Except for the very nasiest of snowy days, my girls wanted to be outside so I dug out a pit in the snow around the front of their house and lined it with straw--they seemed to like it better when they didn't have to stand right on the snow. I threw down some scratch for them and they were happy as clams. It worried me that they were out there without fencing, though, so I threw up some chicken wire. As the snow melted I had to readjust it down, but it seemed to work okay.
This year I'm going to do something about their water because I did have a slight problem with it freezing. I had to go out everyday and put warm water in their waterer. I think I'll try something I read where you put down a cinder block with a simple light socket and bulb inside it. You then set the water down on top of the cinder block. Evidently, the bulb keeps the water just warm enough not to freeze. It's worth a try...
Sorry this is so long, but I wanted to share what I--a true chicken amateur!

--did. It really worked. My girls stayed happy and healthy, their combs remained intact, and best of all, I collected 5-6 eggs every day all winter long (except when I didn't get out there soon enough on super cold days and the eggs froze--the two nesting boxes are attached to the outside of the chicken house with a lid I can lift for access. The girls have access from the inside via two large openings).
-Heather