I'll add the foot should still be padded on the bottom (without antibiotic ointment) and wrapped after the wound has closed. That will continue to relieve pressure from the impact of walking and will help prevent the lesion from coming back. To help keep moisture out, put a piece of waterproof...
You're welcome, @Attila the Hen. We've been dealing with bumblefoot for seven months now. I see chicken feet with my eyes closed and can now identify each of our girls in photos showing only their foot pads. That should go in the "You know you're a chicken lady when" thread..
I agree and my vet does too; some will resolve on their own.
I also agree with you that many more of us are noticing it. Maybe it's because we generally have smaller flocks and maybe we're handling them more often. My chickens like to snuggle, so it's easier for me to notice small changes...