I have two pekin ducks that are eating/drinking/laying just fine but I noticed these dark areas /callouses on their feet. I've been doing Epsom salt baths the past few days and spraying/wrapping with blu kote antimicrobial but seeing no change. Wondering if any of these dark spots are bumblefoot or something else. I've tried peeling the dark spots after soaking, but really have nothing to peel as only one of them is raised (the big scaly one). In pictures I've seen online, there is usually a 'bulb' but I don't see one here. Any help is appreciated!