Maybe some boards around your land stating that any dog found worrying livestock WILL (not may) be shot! And, it's not always city types and their pampered dogs that cause trouble, my flock of tiny Ouessants were killed by a neighbours working collies. A door left unlatched, bored dogs and that was that. The owner was as gutted as I was but I held nothing against him and we remain good friends and neighbours.
As to foxes, I had, at huge expense an enclosure made which is half the size (or more) as a football pitch, clad in deer netting, eight foot high and hung about with the hated barbed wire. It didn't work and all due to released orphan and urban foxes!! You know who they are, they come up to you and say "got any dog food". They scaled netting and barbed wire frequently in daytime and killed everything there. I also don't hold a grudge against the poor foxes who were doing as we would in desperation, but the kind, misguided actions of the "cuddly" fox lovers.