He could be a mix with a 5 toed gene in his history. But for bumblefoot, I would start by bring him into a warm hose, and soaking his foot daily in warm Epsom salts water. What are your temperatures like there? A mixture of Betadine and sugar, made into a paste can be applied to the bumble and dressed for 2-3 days, changing it, to soften the scab in order to remove it and press out any pus inside. Prid drawing salve also works that way.