I did a little more research and found this article, which recommends this:
- Offer tetracycline antibiotics in the water to help control secondary infections. 300mg of Terramycin per gallon of drinking water for 3 days followed by a vitamin supplement in the water.
- Treats scabs with a dilute iodine solution.
- Apply ointment to soften scabs. (Mix 2 tablespoons of sulfur powder with 1/2 cup Vaseline. Apply to affected areas daily until lesion is healed.)
- Mix diluted iodine solutions into the flock’s drinking water. (Iodine solution for drinking water: Mix 1 teaspoon of 1% iodine solution per gallon of water OR 1/2 teaspoon of 2% iodine solution per gallon. Provide as the only source of drinking water until outbreak subsides.)
- Clean coop and run with the objective of removing hot debris from the premises.
- Sanitize drinking water.
Here's the article if you want to read more:
https://www.petpitari.com/2018/12/08/fowl-pox/