My Border collie killed twenty of my chickens on x-mass eave. I think it has to do with training. I got the Border collie from my brother when he could no longer care for her. I would put my money on a good mutt any day. Find a couple breads mixed, that will turn the temperament to what your family needs.
A great paranoeas (sorry for the spelling) is always a good choice,all though it is not a small breed.and they will stay with the live stock if raised with them.
I would think it is a border collie.
The central Asian shepherd dog or Alabai is the best to protect live stocks.They are large and only 2 dogs can protect a 100 sheeps.
The best would be a german shepard the are really good with kids and animals
Anatolian Shepherd, aslong as you are willing to train. They're big, very smart dogs that should have discipline and training early.
Have you considered a maremma? They are able to be trained by living with a herd of any animal that you want them to protect. Once properly trained, they are supposed to be the best guard dog for protecting your small/young livestock against fox or dog attacks.