i was at work and my daughter let my dogs (Cooper - collie, Peanut - Shitzu) out and the neighbor let her dog (sheltie collie?)out and i guess there was a fight and the neighbor claims Cooper killed her dog. i don't know if anyone saw the fight which isn't the point but i guess i just want to know if i have to worry about Cooper doing this again and if he would hurt a human being. He's usually pretty gentle and mellow. I'm wondering if i need to get rid of the dog or what. Both my dogs are not fixed and if they were fixed would it help?? i just want to know if i would be better off getting rid of the dog? When letting him out i usually try to put him on a chain so they aren't running all over the neighborhood.