Hello! We're next door in WV, and even though this is our third winter with chickens, these have been (by far) the coldest one yet! And even though I've read all sorts of stories of people with flocks far north of us and breezing through temperatures far colder and over longer periods, I still had to see to believe (to an extent).
Our coop is a small 2-story affair, so since Friday I closed up all of the screened windows in the 2nd story because that's where the roosts are. The windows on the 1st floor remained open and the pop door opens/closes automatically and I have changed nothing about its timing.
I checked on them this morning around 5AM before I left for work (it was 3F with 25mph winds, and I have no idea the windchill). I opened a side door to take a look and our roo was kind enough to crow in my face, presumably telling me to shut the dang door.
They were all hunkered down on the roosts staring at me like I was crazy, but they were fine. Once the pop door opened and the sun was up, they all piled out like they do any other morning and couldn't seem to care less about the weather.
The only issue we've even had over the past week have been with their waterer. We have a 5-gallon bucket with chicken nipples in it and we keep a bird bath heater in it to keep it thawed. It works great until the temperature drops below 20F. After that, the film of water in the nipples themselves freezes up and they won't budge, even though the water in the bucket remains liquid. So we just switched to a large heated dog bowl 2 days ago and no issues since, even though we have to dump and clean it out every day because they insist on kicking everything they can into it.