Yup, 20 degrees & below zero is No Fun for anyone, bird or human. I will used the oil filled heaters, not often, but here, I do not get teens & 20s weather consistently, months at a time either. We might get a week or 2 of below freezing, then it will warm up above freezing a few days or weeks, then drop again breifly.
I will say this, I do leave some windows open for fresh air & so humidity won't accumulate. Chickens put off a lot of moisture, much more than pigeons, so I learned...ya don't want to see any droplets of condensation on a window! I installed windows in North, South, East & West walls, so I can open & close accordingly, to prevent direct drafts or rain & snow from blowing in. I learned about basic proper ventilation many decades ago when I first got into pigeons. I remember when building my first pigeon loft, the old-timers were telling me how important ventilation is, yet you can't have direct drafts. That was rather confusing to me at first. Many built permanent open slots covered with hardware cloth, but I did not want to do that here, as we get some serious wind at times, hurricanes or Nor'easters. I figured out all I have to do is check the weather, to see what direction the wind is blowing in from, and close that particular window & leave the others open. In summer, windows are open all the way, there are screens. In winter, depending on temperatures or wind, windows are slid half shut or 2/3 shut, or whatever works to still allow ventilation.
Even below freezing, I leave something open a bit, because I do not have other ventilation built in. My coop can be totally sealed, as I made it rodent proof & considered hurricanes & tornadoes. But all windows are never completely shut, can't do that, it gets too hot & humid from the body heat & moisture chickens produce. A wet coop...you do Not want! Old timers told me long ago, a wet loft or coop, is a sick loft or coop. Wet & stinky is no good. So I strive for dry & comfortable, so far over the years, so good.
I want to add, a wonderful invention...the heater for drinking water. I set them up December, I have both types, but prefer the one that goes under the regular waterer, & made sure I got the ones appropriate for the plastic waterers. Just pay attention to the type, based on your type of waterers, whether yours are metal or plastic. I switched to plastic as I like to add ACV to water & the metal waterers will corrode if you add ACV.
Anyway, set them up Nov or Dec, or whatever, before below freezing weather hits, then they're ready, all you gotta do is plug in to turn on when temperatures drop. To me, they're worth their weight in gold. Nothing fancy here with electric, I run a very heavy duty construction grade extension cord & have the weather proof gadget wrapped around where the plugs meet. I did run electric wire & receptacles inside the coop, but the way to plug the extension cord is to another plug, under the coop. We've gotten 4 foot snow drifts, 70mph winds & everything worked, stayed dry & comfortable.
Anyway, best wishes to everyone & your flocks, winters can be brutal.
