We just have the little dogs. I tried getting a larger dog, but she would crash around, inside or outside, and almost tripped me several times. I finally gave her to a friend that had another large dog for her to play with, and she was fine there. We would like to have a guard dog, but not if it is going to be knocking me down, and I get hurt. The little guys are great to alert us if anything is around, and would probably discourage most prowlers from trying to get in. They think they are big dogs, so I do have to be careful to keep them out of the woods where a predator might grab them.