“There is a very natural response to anyone a man finds trespassing on his land.”
If you mean shooting them, the `castle’ doctrine applies to your home—not your outbuildings and curtilage: yard, fields, north forty, etc.
That doesn’t mean you can’t have them in your sights.
Welcome to FR.
The natural response is to tell those who are trespassing to to leave immediately and never trespass again.