Have had a couple of similar situations out in the "Old West" in AZ. USA. Just walk out and ask the guy to stop. Make sure you have a 12 gauge shot gun , with action open, hanging over your shoulder. Works every time, and is perfectly legal providing you do not point it at him. Getting the missus to take a dig. photo of the the episode is great evidence. Then call the local police station and tell them what you have done, so it is on record.
Running around like a head with it's chicken cut off.