This is our first year keeping chickens over winter in Manitoba. It gets quite cold here (to say the least) so it was very important to us to make sure it was warm enough for the chickens in the coop no matter the temperature outside. After a bit of research we decided that we needed a heated waterer, and that we would use the deep compost method.
The heated chicken waterer was the most important item we bought. With daytime highs of -20C and nightime lows of -35C, water in the coop freezes in less than an hour!
Using the deep compost method means that you leave the old straw and chicken poop on the bottom of the coop and put fresh straw on top when needed. That way the old straw on the bottom decomposes, giving off heat, and acts as a thick layer of insulation for the coop.
We found out quickly that in these temperatures the chicken poop below the roosts freezes quickly and would grow like stalagmites, messing with the deep composting method. So on a warm day in January we installed a poop tray. Under the roosts we have a shelf covered with an empty feed bag that we replace when it gets covered with poop. This is helping so much with coop maintenance and the smell.