In this country, if you set a booby trap "set gun or crossbow" and it kills someone, your ass is grass. Thieves are lazy. Make your place difficult to get into by planting prickly bushes etc. I heard of one guy who had three locks on his door. He left one of the unlocked, so, a lock picker would always lock at least one of them!

Sometimes a simple BEWARE OF DOG sign will do. (It's not illegal to lie to a burglar)