Ideal livestock guardian dog

I have thirty sheep and my Great Pyrenees has bonded with them completely. She sleeps with the flock, patrols the perimeter, and has deterred at least one fox attack that I saw evidence of without loss of animals. She is calm and confident, never frantic, and the sheep seem to find her presence reassuring. She is also wonderful with my children who grew up alongside her. A working breed in the best possible sense.