Spraying the soil with Oxine is ineffective. For wet pox, you're going to have to use tweezers to remove all lesions in the mouth. Then swab the mouth with iodine.
If there's lesions in the esophagus or trachea, cull the bird. If you dont, it will starve to death or suffocate. You should be able to see lesions that far back in the mouth.
Fowl pox is spread by infectious lesions that are picked up by other birds, also via the bloodstream through a scrape or cut in the skin.
https://www.merckvetmanual.com/poultry/fowlpox/fowlpox-in-chickens-and-turkeys