An interesting thread, and again one that highlights the continuum of why (and therefore how) we all keep chickens. At one end, some folks look on their chickens as pets, even family. At the other end, some folks (I tend to be more towards this end of the spectrum) look on their chickens as farm animals with specific purpose and cost-benefit. For folks of the former paradigm, insulating and heating and carpeting and so on are a natural consequence of how they wish their pets / friends to be treated. For some of us, those things add cost and complexities that we consider unnecessary. Interestingly enough, the chickens seem to thrive regardless.
My birds live in a coop that is secure from drafts or rain and snow, and kept fairly clean of poop and debris. Although they spend their day free-ranging, they seem to enjoy huddling close together in the coop at night, especially in the colder months. In the warmer part of the year, many of them prefer sleeping on top of the coop (especially the dominant rooster). I take the attitude that they know best what's fine for themselves, and they seem to do just fine.