While individual dogs can vary from their breed descriptions and training is key to peaceful coexistence, I would advise against sled dog breeds (high prey drive), and bird hunting breeds. The AKC has descriptions, pros and cons that can help you decide. It has been my experience that their breed descriptions are accurate. As such, some dog breeds are better at guarding than others. For instance, malamutes are horrible guard dogs since they love anyone's attention and are a bit lazy, while german shepherds are sentrys (my experience thus far). However malamutes have a high prey drive and chase to kill, while the gsd bark runs to scare away. I think the great pyrones (sp?) is a breed specifically for livestock protection.