Hi,
Someone mentioned Border Collie as a guard dog.
I would say this as an experienced owner of a Border Collie, they are fantastic dogs, great guards and I would not be without my dog. But it depends on the dog/owner relationship.
I have a dog, and when I got him, I was told if I hadn't had experience with Collies I would not have got him. They are lush dogs, daft as a brush and highly intelligent, but they are strong mentally too.
You have to be boss with these dogs, and their intelligence can make them sly and difficult on times. It can be wearing, you can not let your guard down with them because they will constantly take adantage.
My dog comes from working parents and he is really good, bit jealous of the girls . but he is safe around them, but I would never trust him 100%.
So I would advise to go with the Great Pyr if possible. Lovely dog and also to be trusted more.
My Collie still scares the postman after 4 years, but if he was loose he is a total baby. All attention has to be for him, and he's a big boy now, no matter, wherever possible he has to be top dog. Plus he has selective hearing some times... lol...
They need a lot of stimulation to stop intelligence going the wrong way.
Jena.