Generally we wait to vaccinate foals until they're a little older and good and strong. Less chance of them having trouble fighting the small dose of the disease and forming antibodies. This one didn't get good colostrum and had to get 2 liters of plasma, so we have to be careful. It stayed strong and healthy the whole way through but thats not something to mess with.
Thanks for the input guys. I also am a firm beleiver in shoot shovel and shut up, and have taken care of lots of other varmints that way. I'll probably just keep an eye out for the fox and see if I can't take care of him when he comes to visit. I just thought I might have found a more immediate solution. From my experience and from talking to friends around here, game wardens and park rangers around here sort of think they're supercop and don't practice much common sense. I'd rather not get them involved as it would probably lead to animal control stalking my pasture with one of those poles with a cable loop on the end
If it shows up again I'll either introduce it to the old scatter (but not much) gun 1897 winchester 12 gauge, or a .22LR