Soak the foot in warm Epsom salt for 15 to 20 minutes daily. With clean tools, gently remove the scab and the hard plug underneath. Pack with antibiotic ointment, bandage with vet wrap, and change daily. Severe cases need a vet. Lower the roost height to reduce jump impact.
Prevention
Sand or smooth rough roosts. Keep roost height under 18 inches for heavy breeds. Check feet weekly. Keep the run free of sharp objects.