Drake with Bumblefoot

My white crested drake has bumblefoot. It is pretty large, about the size of a marble on his heel. There have been no symptoms until yesterday when I noticed him limping. He is inside now in a large wire dog crate. I have soaked his feet in epsom salts and warm water to get all of the crusties and dirt off. I plan to take and post pics later.

The advice I got from a vet, because the bumble is large, was to try corn and callous remover. She said to soak for as long as he will stand still, clean area with alcohol, apply corn remover and wrap. Repeating this once a day. Has anyone ever tried the corn remover? It's main ingredient is salicylic acid.