Bumblefoot normally has a round dark in color scab on the bottom of the footpad, it doesnt look like bumblefoot to me. Your bird appears to be a pullet and not a grown hen. I wouldve suspected possibly gout if she's a grown hen. Otherwise it might be dermatitis. If it's dermatitis, I recommend you purchase Avian Super Pack and mix it in water for her to drink. Dosage is 1/2 teaspoon per gallon of water for 5 days, make a fresh mixture daily. She may be lacking biotin and other minerals in her diet, Avian Super Pack will take care of that. It can be purchased from Jefferslivestock.com if your feed store doesnt carry it.