Just in case you're all wondering, it wasn't bumblefoot It cleared up nicely and now the little (or big, now, lol) duckie is out free ranging with the older birds and his duckling friends. They grow up so fast
Since it wasn't bumblefoot, he just ended up having me put neosporin without pain relief - very important as the pain relief stuff is toxic to birds - on the wound once a day and soak his foot in an epsom salt soak once a day as well. And that did the trick!