Looking at the pictures again....did these bumbles just develop or were they there when you got them? Have you always used the shavings? Just trying to figure things out. These guys are babies and usually you don't see it with them. Suggestion, if you are able, see if you can find a smaller, finer shavings or sawdust for bedding. It could be as simple as their feet not being hard yet and the shavings being a bit rough.
I have ducks and ducks and more ducks, lol. And geese too. I've seen my share of bumbles because they will not stay out of the raspberry bushes, the brats. They get a cut or puncture and then run merrily through the muck and mire opening themselves up for the staph infection we call bumble foot. If it's allowed to go for too long, untreated and it gets bad enough to reach the bone...you have major problems. They can lose their lives to it. The best thing to do is what you've done...you saw it and are now watching. Treat with the iodine topically and watch for swelling, heat in the affected foot, loss of appetite and not drinking. If any of these show up, immediately give an antibiotic. I start with Duramycin 10, 1/2 tbls. per gallon of water and it usually is strong enough to get them gone. Bumbles can take a long time to go away if they are big, even with surgery, so I try to keep things as noninvasive as possible. Pulling the scab after soaking in warm water is routine for the larger bumbles, as well as cleaning out any of the gunk I can readily get with a pair of tweezers. Before doing this, make sure everything is clean and sterilized, just as you'd want it to be for yourself. I do not wrap the feet after doing the surgery. You never want to do that with any kind of iodine! I just repaint them with the iodine, dry it, either by blowing on it or putting them into a confined, clean space until it has dried before letting them back with the others. Heck, last Summer there was a point when I had 8 ducks with bumbles. Most were not bad and i just scooped them as they came out of their pen to free range and wiped them with a sanitizing wipe and then just painted the bumbles, letting them dry for a minute or so and turning them loose. They all healed, no more bumbles right now, but the raspberry bushes will call them again and in spite of heavy pruning, I know the idiots will be giving me practice with healing them again this year. Welcome to a duck keeper's world, lol!
