Yikes! Yes that is bumblefoot. I’ve heard people say it’s more common in ducks but I personally have never dealt with it in mine, just my chickens.
I’d say it might be the wood chips. I use them too for my ducks and my chickens, but my ducks have a very shallow layer which leaves bare dirt exposed most of the time. I’ve had chickens get splinters from it that turns into bumblefoot and that might be what’s going on with yours. If I were you, I would switch to something like sand which shouldn’t be as harsh on those little feet.
These look like they’re at the ideal stage to remove and treat which is good. You’ll need to soak their feet (I usually do about 15-20 minutes) to soften the black scabs. Generally once they are softened they are lose and able to be carefully pulled off. Usually the kernel (the infection itself) will be attached. It should be whitish/yellow in color and it’s actually mostly just pus. You’ll be able to tell when you’ve pulled it out. I treat with several products; first flush out with saline (and may use iodine if there’s any bleeding), then spray Vetericyn Plus Poultry, fill the hollow with Neosporin (WITHOUT pain relief, do not use anything with a numbing agent), then cover with gauze and wrap with vet wrap (someone may recommend a different wrapping process though for ducks). You need to repeat that treatment daily until it has healed. Some people like to give epsom soaks during the healing process too but I honestly don’t think it’s necessary if you don’t want to spend the time.
Hope this helps!
