They are not, I can assure you. Llamas can be if they are from a guarding line. Some have the instincts and some don't. A rare alpaca may have the instinct, but they are not as big or tough as some might think. Adult females can be around 90 to 150 pounds. Intact males might make a decent guard and while slightly larger, they are something you do not want around, and geldings don't usually have the drive to be gaurd-ish.I want to get alpacas to put with my chickens. They’re supposed to be good flock guards.