Stumbled across this last night. GPS collars to control grazing areas! Looks like they work best in larger pastures than mine, and the cost is still quite high, but if we can make a smartphone cheap, no reason why the cost of the collars couldn’t come down. Predator protection was my other thought, but a guardian animal could take care of that. This could be a real game changer with silvopasture/agroforestry where tree protection and fence moving is a large expense in terms of labor and materials.