The ones I get become swollen, often from frostbite or that compounded with another issue. They either stay swollen and blistered before healing, or the foot eventually dies. That's what happened to One Leg and Knuckles, but they were still mobile. Usually if it starts dying, they give up and I have to put them down.
We've had birds over 10 years and they did just fine in less shelter than they've had these last few years and now we're having issues. It's not that I brought in bad quality breeding somewhere either, because it's multiple groups with unrelated birds. I had two males last year that bounded back with little damage that had literally frozen solid feet. He went to roost one night, couldn't get a grip and fell 20 feet almost on top of me.
Honestly this is a part of why I'm so badly wanting to love. Our winters are absolutely horrendous.
Once they suffer from frost bite, their feet never do well in the cold. The cold will forever effect the circulation, cause swelling, reduce strength and gripping. Make sure your roost bars are wide enough so their breast fluff covers their toes completely. Use a 2x4 with the 4 side up, no round bars. I use a 4x4, cant even see a claw. I cover my roost bars too with an old towel stapled to the bar. This keeps feet really warm. You might have birds with previous frost bite roost on the floor in a pile of hay, cage them if you have to so they sit on their feet all winter long at night.

