and whether it is or not, I think the treatment would be the same so what you’re doing is great with the Epson salt soaks and applying an ointment after to keep it moist, some like Neosporin ))without any pain relief in it, )) and then bandage it with a gauze pad and wrap it with Vet wrap I...
https://www.backyardchickens.com/articles/frostbite-what-to-know-about-injury-care-and-recovery.78168/
Has it been cold where you live? What kind of floor do your ducks stand on? is there any metal?