It needs surgery to try to remove the pus from inside if possible. Soak again in very warm Epsom salt to soften.
Then have all of your supplies ready. Sharp instrument sterilized for cutting into the lump. Sixteen inch strips of one-inch wide Vetrap. (You need to cut the roll lengthwise to get this correct size) Get it where the horse supplies are in the feed store. Non-stick gauze pad cut to size.
Have Vetericyn (also where the horse junk is), and antibiotic ointment handy. Wrap the chicken tightly in a towel to control wings and feet. Cut across the scab and make about a half inch incision. This will expose the pus if there's any. Scrape or pull it out. It will be solid waxy stuff. There may also be some stringy white stuff that won't scrape out. Ignore it.
Flush well with Betadine or saline, dry, and spray Vetericyn on the wound. Let dry and put the ointment on it, generously. Place the gauze pad on the wound and lay the Vetrap strip end over the gauze pad with the short end sticking up towards the leg. Bring the long end down between the toes and back up the outside of the foot and across the short end, locking it in place.
Continue to wrap the wound by cris-crossing the wound until it's securly covered, and finish by wrapping the end around the shank (ankle), pressing securely until it adheres to itself. The chicken shouldn't be able to work it loose if you did it right.
