I'd almost say that there's not truly a livestock guardian breed that's born ready to serve. There are dogs whose characteristics make them more easily trainable and affable toward this duty, but even within breeds, each dog is different. It's actually in a dog's natural prey drive to kill a chicken or anything else that's hopping around and furry or feathery, but some dog breeds and some dogs regardless of breed can learn to temper this more than others.
It's often been said that a good farm dog isn't made, it's born, but I think it's a lot of both. I've learned that it takes about two years to train a good, dependable livestock guardian. Of course, some come into it more naturally than others, and some never will. Before getting a dog, you may need to commit to the idea that it will be part of your lives regardless of it's ability to fulfill this duty.
I'm sure there are plenty of exceptions to this, but I don't hold to the idea of sticking a puppy in a field or barn and thinking it will naturally figure things out. Although I don't think it needs to be sleeping in your bed either. All dogs need to be taught their place in the pack along with what is expected of them, and most dogs will thrive when this is provided with a strict, loving hand.
Speaking from decades of experience in dog ownership and training, I'll just throw this out there: When it comes to most things in life, including dogs, you get what you get. But if you work hard to mold your canine companion into a job and life they'll love, you'll usually be successful. So pick the breed AND dog that suits you and your lifestyle and that you want to spend a lifetime with, and then train train train and it will usually work out well, regardless of his/her ability to be a LGD.
PS Pictured is my pretty 100 lbs lab/pyre mix guarding our land. Best farm girl ever.
