Years ago I had three Dobermans, all raised from pups and certainly not herding type dogs, but they decided on their own that the rabbits and chickens were their responsibility and I never lost a single one to predators. Or to one of them.A well trained one.
Breed isn't that important, training is what needs to be focused on. If your can get a dog that has already been with/behaves well with small animals or a puppy so that it doesn't have "pre-set" bad habits that would be easiest, but any dog can work. It really all depends on how much training you are able to put in.
Once upon a time we had a Golden Retriever. That dog loved everybody and any critter we introduced her to.was looking for other peoples opinions on dog breeds that are good to have around rabbits. we are looking to add a dog to our family when we get moved and settled.
I have to agree with this 100%Our Golden Retriever cross would gently catch our escaped rabbits for us, we just had to point out which one we wanted caught. He would carefully catch it and bring it back to us with never so much as a scratch on it, live and well.
If someone would call us in a panic that their livestock had been attacked by a dog, it was invariably a German Shepherd or Collie cross that was the culprit. They loved the chase, would catch and kill or maim the prey, and then move on to the next fun chase. You've seen dogs grab and shake their favorite toy--looks cute until the 'toy' is a pet, and the quick shake breaks the neck.
Not saying all Shepherds or Collies are bad, after all, they are trained to work with livestock--but untrained crosses may still have the urge to chase the animals, but not know what to do when they caught them. After all, other breeds are bred to catch and destroy 'varmits'. A breed with the 'follow animal' instinct crossed with the 'kill it' instinct can be a bad combination.