Strongly agree that ventilation is the most important thing for chickens. We had chickens in the Interior of Alaska (the coldest part of the state, and one of the coldest inhabited parts of North America), in a somewhat drafty little barn (shared with a couple of goats and a few rabbit cages), and while we did lose a few combs and even a toe or two, the birds survived and continued laying. If I was back there again (I'm too old to like seven months of snow-on-the-ground!), I'd probably build a tighter small barn, and give the chickens not only more bedding, but no roosts in the winter, so they'd have to sleep with their feet on the bedding pack, which self-heats. But I would also put some kind of heat-exchanger ventilation system in it. We didn't have that option back then, as we didn't have electricity where we were living.
Later on, we lived in central NH for a number of years, and had some chickens who decided that their roosting place was either in the trees across the road, or in the branches of the big ancient amur honeysuckle bush next to the house. Even through thirty degrees below zero, with snow, or rain in the summer. I don't remember ever losing a hen to the winter, although the owls picked off a few of them.
If you have really cold winters, select chickens suited to the climate - large-bodied and small-combed. I don't like feathered feet, myself. Some people recommend them for cold climates, but in my experience with some Light Brahmas, the foot feathering just collected ice balls or mud balls, depending on what time of year it was. And they lost just as many toes as the hens who didn't have feathered feet.
If you don't live in a climate that gets really cold winters, then the only factor you need to worry about is ventilation. Keep them dry and out of the wind as much as possible, but the three-sided sheds, with one side wire, talked about in the book mentioned above (which were used in, IIRC, Vermont or upstate NY), are completely adequate. If you are where it gets really cold in the winter (way below zero, F), you can build the three-sided shed, but have shutters to close at night in really cold weather. Just make sure to open them first thing in the morning.
Also, use deep bedding. Someone I used to know who had a farm in upstate NY would completely fill her hen-house with leaves every fall. Filled to the ceiling! Then throw the hens in and let them pack it down. Clean it out in the spring, and there is some of the best stuff for the garden that you ever saw. (Have a few bags of leaves stored to add if they need clean bedding, but don't clean it out until spring.)
Another very helpful thing is to have a heated waterer, so they always have water to drink. They can get by with snow, if they have access to the outdoors, but they'll do better with water. (Again, we didn't have that option when we were at the off-grid place in Alaska - I would take hot water out to all of the animals twice a day. You really don't want to have very many animals if you have to do that.)