I agree with the others, your pigeons (assuming they are all well-feathered and in good health) should be fine without additional heating based on your description of where they are being housed. Just feed them well and include corn in their feed (whole corn, or if your birds are a bit more picky or a smaller breed, popcorn), and make sure they have clean water which is not frozen over.
I knew of someone in Alaska who had Oriental Rollers and simply kept them in a regular large, draft free loft outdoors and they were healthy and stayed warm with just their own body heat. No additional bedding besides in nests, part wood floor and part wire, good ventilation but not drafty, and no additional heat (besides little heaters under the water founts to keep them from freezing as much). I don't know exactly how cold it got in the winter there, but I would imagine it could get as cold or even colder than where you are.
Good luck with your birds
I knew of someone in Alaska who had Oriental Rollers and simply kept them in a regular large, draft free loft outdoors and they were healthy and stayed warm with just their own body heat. No additional bedding besides in nests, part wood floor and part wire, good ventilation but not drafty, and no additional heat (besides little heaters under the water founts to keep them from freezing as much). I don't know exactly how cold it got in the winter there, but I would imagine it could get as cold or even colder than where you are.
Good luck with your birds
