What is the pad on for, is there any chance you can get it taken off? I would be concerned about bacteria building up under there and not being able to clean it properly. My horses heels look similar to his after coming to the end of a wet winter. My farrier has had me washing and drying the feet every second day and applying lots of manuka honey which is antibacterial and provides a barrier between the hoof/heels and the wet ground. That's about all I can offer since I am only really learning about the care of horses feet now myself.