There are two different types of mange that goats get - chorioptic (on the heel and lower leg) and sarcoptic (all over the body). In order to treat it properly a vet should make the diagnosis -s/e can then also prescribe the required Ivermectin based drug (probably an injection, twice a couple of weeks apart or so).
BUT as your boy seems to have a bit of a chequered history the skin lesions could also be from a mineral/vitamin deficiency - only a vet can have a look at this. If you want to get your boy sorted get him checked out!
And no, other than with the precise use of a gun I don't think you can sort out the mange problem of your local fox population....