There is also an ugly, bad smelling indoor troll who spends most days in bed and buying trash.
It's possible tho. I have a pekingese who sleeps most of the time and is pretty lazy. These original purpose of this breed was to be a companion for chinese noblewomen. Last year I was on vacation and the house I stayed in was on a tiny farm surrounded by a fence. From day 1 until I left my tiny, lazy dog turned into a tiny version of a guard dog, warning me of "intruders" aka neighboors walking past the fence and then following them while barking loudly. She never did this at home and after the vacation was over she returned to her old self. It was weird, man. Adorable but weird.
If a Pekingese can be a guard dog, the tranch dogs who are bigger and stronger can too...but the tranchers would have to make the effort to train them...which of course they won't.