Most of my coops are like yours, Believer. The Loew's playhouse, right?
My silkie coop is one 4x4. The LF pen is two of those with an 8' shed built between them. I have covered the windows in all three of those with plastic sheeting. The AM coop and banty coop I built from scratch. The AM coop is on my BYC page and the banty coop is a smaller version of the same. The large one is 3'x8' and the smaller 3'x4'. The mesh on both of those is currently covered. Both of the homemade ones are raised off the ground. The other two sit on the ground.
All of that being said, I open coop doors every morning no matter what the temps. The chickens are free to come and go as they please. I have found that they are happy out in the runs unless the temps fall into the single digits. I do take out hot water every morning when it is below freezing and the occasional bowl of oatmeal, but other than that they just kind of deal with life. All four runs get good winter sunlight and the chickens seem to just follow the sun around. Even the little tiny silkie babies out there right now seem pleased as punch to be out in the runs scratching around. When it is rainy or snowy, all of the chickens vanish either back up in the coops or under them. Given that this snow has stuck around though I have noticed chicks and chickens out in the snow doing their thing. It doesn't seem to bother them at all.
I worry more in the summer than I do in the winter. Mine really fatten up and fill out with feathers in the winter. When they get cold they huddle up together and share warmth. In the summer I worry about them falling over with heat exhaustion and spend a lot more time trying to keep them cool than I ever do trying to keep them warm. They have a really high body temperature themselves.
All of that being said, I open coop doors every morning no matter what the temps. The chickens are free to come and go as they please. I have found that they are happy out in the runs unless the temps fall into the single digits. I do take out hot water every morning when it is below freezing and the occasional bowl of oatmeal, but other than that they just kind of deal with life. All four runs get good winter sunlight and the chickens seem to just follow the sun around. Even the little tiny silkie babies out there right now seem pleased as punch to be out in the runs scratching around. When it is rainy or snowy, all of the chickens vanish either back up in the coops or under them. Given that this snow has stuck around though I have noticed chicks and chickens out in the snow doing their thing. It doesn't seem to bother them at all.
I worry more in the summer than I do in the winter. Mine really fatten up and fill out with feathers in the winter. When they get cold they huddle up together and share warmth. In the summer I worry about them falling over with heat exhaustion and spend a lot more time trying to keep them cool than I ever do trying to keep them warm. They have a really high body temperature themselves.