This is a VERY close friend of mine, she is the one I buy my Pyrs from. They are NOT cheap but OMG they are worth their weight in GOLD! and that's alot of weight
http://bar6diamondranch.com/lgds.html LOL It's about $300 to fly an 80 lb dog, our female from her was 6 months when we got her. if you get a puppy it's cheaper. She is very knowlegable and is super helpful even if you don't buy a dog from her.
They get along with any family dogs you already have, they learn you are master and will tollerate anything you allow around the animals.
They are also the only LGD who protects against air predators.
They are very different to raise though, I would totally suggest investing in a grown and prooven dog to ensure it was raised by a good breeder. Our male got too much attention from us as a young dog and is now a nightmare to keep IN with the goats- he wants to get out and go visit everyone (humans) but people get scared of him due to his size and call on him all the time. Humane society fee's add up quickly. If you get a good dog or a pup and raise it PROPARLY (which is SUPER hard because you
have to ignore them and leave them to bond with the animals you want them to guard) they will be the best asset to your opperation ever.
As to how they let you know if an animal is sick, close to kidding etc- they will do any number of things:
hang close to it and make conatant eye contact with you (Like trying to send you a mental message)
Moses will pace and whine at you then walk to the animal then back to you or will lay with it and refuse to move- my friends dog did that, laid out in the back 40 with a doe in labor and wouldn't come in to eat, so out they go to see why and found a doe struggling to kid...
Our female, Pebbles BARKS at you insessantly, refuses to stop, until you figure out what she's demanding or what's wrong. This took us a LONG time at first, but now we fgure out how close we are to what the animals need based on how loud she barks. If we're close to it she'll quiet down or stop completely if we're doing what she wants, if we're way off she jumps and barks really loud. I'm not joking, she plays 'hot and cold' very smart dogs LOL she'll do this over something as small as them needing fresh water (which they get 2 times daily anyways)
Moses herds the does to safety if he's concerned about something, he'll make them stay in the barn etc. He even goes out, gathers momma's when new babies wake for a meal in the barn, bring momma's in to nurse then escort them back out to graze and come back to watch the babies nap while the moms are out and about.
And Pebbles checks all the goats hay, while we feed she will sample the hay and sniff through it and if it has a dead mouse in it, rat poo, mold anything dangerous she won't let the goats near it until we clean out the feeder and re-feed. Probably saved us thousands in dead animals who didn't get listeriosis etc... you just can't put a price on these dogs, the stories are endless!