@flyladyrocks
Assuming this is frostbite....
I know a person from Canada that had one of her birds step into the waterer and the foot froze immediately. She brought the bird into the house for recovery. The only thing she used on the foot was coconut oil. Seriously. Just coconut oil. Coconut oil has anti-fungal and anti-bacterial properties. She kept a close eye on the foot to be sure there was no infection setting in and, since there wasn't, continued to use the coconut oil throughout the dry-up and fall-off.
The bird recovered well, had to learn to walk with the missing toes, but seemed to do quite well.