It was -18 here the other night. I'm pretty sure if I stuck a pigeon in my (warmer than -18) freezer, it would be solid in the morning. So how come all of the dickie birds are not frozen and dead?

They all huddle together in one huge bird hug.

Have a look in your attic. I can guarantee that there'll be 3 owls, 4 starlings and an egret cuddling at the moment. (Scientifically that is the optimal bird:warmth ratio. The 'hidden truth' is that sparrows try to sneak into the inside for extra warmth and sadly suffocate themselves, leading to the much documented sparrow drought.)

If you find a snow owl, then your heating up.

If you find an ostrich, then you are in the wrong country.

Well. some birds will have been unlucky and succumbed to the cold, but in general as long as they find enough food to keep their metabolism ticking over birds cope surprisingly well with the cold.
Feathers were originally evolved as simple display structures, but their great potential as insulators was soon found by the theropod dinosaurs that were the immediate ancestors of modern birds.
Feathers really do kick arse,even compared with the best mammal fur, think about it, the terrestial vertebrates found in the most extreme cold are birds – Emperor penguins
Does that answer the question?