a well trained herding dogs is perfectly fine, happy has VERY strong herding instinct and she would not dream of hurting a small animals, ALL of my herding dogs have very strong instinct and they are all very gentle with the critters, Ripley(terrier) is even perfectly safe with the critters, perky(JRT) is the only dogs that is not safe with critters, I would say it all has to do with the dog, NOT the breed.