[QUOTE=cayuse;8218100]
We do have a fox or two that live up behind our manure pile. I see them occasionally sunbathing along the lot line. Are they something to worry about with minis?[/QUOTE]
Foxes should not bother your mini. They are small and typically shy. Their diet consists of insects, small birds, small reptiles, rodents, eggs, and plants. I would be shocked to hear about them attacking a horse, even a mini! We also have coyotes, which are bigger and hunt in pairs or small groups, and they won’t bother my mini donkey. I think you’re safe there.
Caveat: rabies, which you mentioned, can cause otherwise non-predatory animals to do really weird things. My mini donkey was attacked by a raccoon last year. I saw it happen and still can’t believe it. It walked right up behind him and just leapt up on his haunches. Thankfully it basically just bear hugged him then bounced off and ran away, and didn’t draw any blood. So I suppose it’s possible that a rabid fox could attack your mini but it’s could happen with any rabid animal or any of your horses/dogs/whatever.
Actually I like the foxes to hang out around my barn and pasture because they take care of the rodents. 
On your fencing question, my 36" tall mini donkey is well contained by my 4-board fence around the pasture, the wire mesh with top board around the dry lot, and the very short two-strand electrified Horseguard tape set on step-in posts (cross-fencing in pasture). He will push out of his stall if you give him the chance but hasn’t shown any interest in testing fences.
