My biggest question: will chickens free range in the winter? Snow? Or should I keep them in the coop more?
Chickens hate change. Waking up to a strange white world is a big change. It usually takes two or thee days for chickens that wake up to a strange white world to venture out into it. Even then, if helps for them to have a reason to go out. Food can be a good reason.
These photos were taken when I was in Arkansas. The most snow I measured was about 9" deep, nothing like yours. That snow fell mostly at night. I always leave my pop door open and let them decide what they want to do. It took two or three days before the boldest went out in it. There was grass and weeds sticking up above the snow so they could forage a bit. They made a trail to my compost pile to check it out as it is a great food source. There were trails to some places where they usually hang out. Some never left the coop until the snow melted, some spent a lot of time out in it.
The day I took this photo this 1" of snow fell during the day after they were already out. The change was gradual enough that they never got frightened and stayed out.
It was +4 F when I took this photo, you can see the ice from emptying the rubber water bowl. I left the pop door open and they decided to go outside. It was a calm morning. If a cold wind strong enough to ruffle their feathers had been blowing they would not have been out there. Their down traps tiny air bubbles in it, that's what insulates them and makes down such a good insulator for our clothing. If a wind releases those air bubbles they can get cold. You can see how much the cold bothers their feet, by the way.
It hit 35* (ferenheit)and the coop was 36* even with all the chickens in it.
In my opinion, not a problem. Your job is not to keep your chickens warm, your job is to allow them to keep themselves warm. Something like the wild birds that overwinter where you are. The difference is that they have the freedom to decide where they want to be. We take that flexibility away from our birds when we confine them.
One danger is a breeze that ruffles their feathers. If your coop becomes a wind tunnel they can have problems. You don't want a roost where the wind blows over it. A little air movement isn't bad, it's when it ruffles feathers it gets bad. An easy way for me to achieve that is to have the ventilation openings over their heads when they are on the roosts. Any breezes caused by that is above them.
The other danger is frostbite. As you should know from where you live, moisture is a big component of the risk of frostbite. If you go outside in cold weather with wet hands or a wet face you can have problems. But if you stay dry you are at much less risk. Same with the chickens.
In a coop the moisture can come from their breathing, their poop, or any thawed water. So you need to be able to remove that moisture. That takes ventilation. How much ventilation? I wish I had a good answer. I'm not one that believes that if you have 143 square inches per bird you are doomed to utter devastation but with 144 square inches you have utopia. That 1 square feet is a general guideline that will keep most people out of trouble even of the worst conditions. For many of us it is overkill, for a few it may not be enough. I can't tell from your photos how high your highest roost is, can you lave that foot open at the top and breezes still be above their heads? If you are keeping heat in you might be keeping moisture in.
I remember as a kid chickens sleeping in trees with the overnight lows around -10 Fahrenheit. Minus 10. Those chickens did not get frostbite and did not freeze to death. They were not on a dead branch of a tree overlooking a bluff and squawking defiantly into the teeth of a blizzard. They were in a pretty sheltered place out of the wind and you can't get much better ventilation than sleeping in a tree. I have not kept chickens in truly cold temperatures, the way I read Alaskan's article things change around -20 F.
How much more should I feed?
The article stated more orientation in their diet but layer feed only hits up to 16%, should I be feeding a different type of feed?
You can get a lot of different opinions on this. I just free feed 16% protein and call it good. They eat how much they want to. But it's not about protein anyway. They mainly burn carbohydrates to generate body heat. In my opinion, the amount of protein is not that relevant as far as keeping them warm.
