Points well taken I think (in many cases). Fact is 17 of my chickens would rather sleep in a coop in the summer than stay outside, sleep on roosts, etc, etc, and all the other things that you all propose. Maybe it's the breed. Mine are red. They are mature size too. Not all my chickens want to sleep in a coop by the way, but those do.
Those are the facts. Human wisdom, experience, etc. do not change a simple fact of nature. As one engineer said in a meeting: one piece of factual, verifiable data is worth more than a thousand expert opinions. He was indeed right and his products always worked right. I'm an engineer too by the way.
You are in Finland. Yes, you indeed see the cold. Your summers are no comparison to ours. I'm at the same latitude as Athens, Greece.
Thanks, for helping. I'm an engineer. I take an receive input pretty well, but I can not ignore what my eyes see or my ears hear. If I could, then I would be a politician.
From what I can see, from your posts, you have never taken care of ADULT chickens through a cold winter. You raised some chicks, with a heatlamp in that box. Chicks do not have the same sq.ft. requirements as full grown birds. You can get away with raising a bunch of chicks in a small space, but it won't go well with full grown birds. From what you have posted, you don't have a clue about proper fresh air flow/ventilation needs with a chicken coop. Not only do you need plenty of it, for the summer/warmer months, but it is just as important, IMO, even more so, in the winter. Where I live, I can get summer temps over 100, with suffocating humidity. Then, in winter, I can get temps into the low single digits, not including windchill.
Chickens may have originated in Veitnam, but with centuries of breeding, we have birds today that are faaaaaaaaaaaaaaaar removed from their tropical ancestors. Chickens today, outside of those tropical breeds, are built to handle the cold. Fact is, they handle cold a whole lot better than 100 degree heat. Adult chickens do not, and will not huddle up in a pile, to stay warm in the winter. But what they will do, is generate A LOT of humidity/moisture just from breathing. And if you don't provide enough ventilation/fresh air flow in the winter, you are going to have problems. If that moisture isn't vented out of the coop, in the winter, it will freeze on the inside surfaces of the coop, and on the birds themselves, NOT good. That little door your coop has, is not going to provide no where near enough fresh air flow, summer or winter.
Then, there is the problem with the amnonia gases from their waste. If not properly ventilated, those gases will burn the chicken's lungs out. Sometimes, chickens may spend a bit more time in the coop, during winter than out, especially if there is snow on the ground. I've seen mine stay in for over two weeks straight. The popdoor was open for them to come out, but they choose to stay in. If you get snow, and your 17 birds decide to stay in that coop, they are going to load that box up with waste, and all the nasty gases that come with it. Also, adult chickens don't like to be crowded, they need floor space. Most people recommend 4 sq.ft. per adult standard, some go with 2 sq.ft. minimum, but the more room the better. If they are kept in crowded condition, they will start tearing away at each other, and once blood is drawn, they can turn into feathered sharks.
What I have described IS facts of nature, as far as chickens go. It is a proven, and well known fact, that they REQUIRE sufficient fresh air exchange/ventilation in their coops. It is a known, and proven fact that chickens can generate mass quantities of CO2 and humidity just from breathing. And that needs to be removed from a coop by proper ventilation, and the coop needs to be properly sized for the number of birds kept in it. And, it is a known fact, that chickens have delicate lungs, that can be damaged by foul air in a improperly ventilated coop.
Now, you can go on ahead with what you got, I wouldn't try it. I look forward to, around the middle of Dec, an update post from you, telling us how your 17 birds are doing in that box.