Maybe you don’t have cold hardy breeds. Minnesota chicken keeper here. When I first started keeping chickens, I’d close the coop up tight in the winter and put a heat lamp in there. Every spring I’d have unhealthy, frostbit birds. Once I stopped doing that and keeping them in an unheated, well-ventilated coop in the winter, they have been so much healthier. They acclimate to the cold by growing more down as the weather gets colder. We get down to the -30s here, sometimes for days and nights on end. There is way less frostbite in a well ventilated coop than one in which the chickens are locked up tight. You go ahead and raise your chickens in a way that works for you, but calling people stupid because they don’t do it the same way is uncalled for. (PS - I’ve been raising chickens for almost 40 years, so I’ve had a bit of time to figure this winter housing thing out.)