Rescue LGD sisters 7 months old never trained

I just got 2 Great Pyrenees sisters that are 7 months old.  They were born in a goat herd and have had minimal to no human interaction.  The owners had to give up the goat herd and the pups have been in a barn stall for 30 days.  They are both very shy and timid, actually cower, around me.  I have had them for 1+ week and still am not able to get close to one of them.  Lilly lets me lead her now but Rose will not even lick my hand.  I have them in a big barn with an open stall that they can come and go as they like.  When I take Lilly out for a short walk around the sheep fence, Rose freaks out inside the barn.  I have read about cabling the dogs inside the sheep fencing (electric netting) but am not sure this is okay.  Any advise is greatly appreciated.  I am willing to invest in a training book, but really need steps to make the dogs successful LGDs.  My goal is to show them they are great confident guard dogs to my small sheep herd.  I am willing to put in the time and have tons of patience.  I just want to do right by them and the sheep.  Thanks

I have had a lot of rescue dogs who show signs of trauma (how I interpret the cowering) and the big fix is time.  Treat them gently and lovingly for long enough, and they will come to love you.  But it can take a year sometimes.  

As for Great Pyrs, I only have the one, and he's a pet.  He wouldn't come inside at first because he'd been hit for poking his head into cool air-conditioned spaces at the place we rescued him.  We had to coax him, and he skulked in hallways for a week.  But now he just takes his pick of the approved dog furnitures and sleeping mats, and the other (much smaller) dogs just have to suck it up.  "Where does a 150lb dog sleep?  Wherever he wants!"

Don't let anybody tell you these animals can't be socialized to be safe around kids and strangers; they are stubborn and self-directed but they are as emotionally needy as any other dog.  Standard dog training doesn't work on ours; he "knows" what he needs to do and is just puzzled by human input.  But he's gentle and playful and careful and sweet, even when he's whirling and playing in a tiny interior space.  

I don't have any knowledge/advice about keeping these guys on a line.  We don't.  

What I can say is that there's never much point in being stern with a Pyr; they have tender feelings and won't understand, but harsh words will inhibit their joy in seeing and interacting with you.  Which (plus a well-established pattern of good food bribes) is the only thing that works (sorta) when "training" (LOL) stuff like recall (getting them to come to you).  

Our enormous galoot is a big baby and a spoiled pet, but I wouldn't have him any other way.  There's a lot of internet advice out there saying to treat these dogs like livestock and advising against socializing them to enjoy your company.  And then they mention as an afterthought that visitors are terrified and they can't take the animal to a vet.  Gosh, I wonder why?

This has worked for me :   get some food with a good odor to it ....like hot baked  chicken.  Go and sit down on ground level with them (make sure cell phone is shut off).  Eat chicken and offer some to them. But they have to come to you to get it.  Provide small amounts of food each time.  You do not  want them to be able to grab all the food at once and run. This process could take an hour or more.

What John said.

The dogs have to understand that they are safe with you and trust you.  Food is an awesome way to do this - its a nervous system thing that makes it hard for them to simultaneously eat AND be afraid.  It might take a while - like many sessions.  Don't give up b/c it doesn't work magic the first time - go with small success each time.  Talk to them, be encouraging but get down, be still(ish) and let them come to you.  

The 1st time they might just decide to watch you.  Actually, just watching you (instead of turning heads away) is good.
The 2nd time they might approach, but retreat when offered food.
The 3rd time they might take a bit of food and then retreat.
The 4th time they might take two pieces of food.

Eventually they will lay heads in your lap.  Time & Patience.

I guess I need to add: repeat daily.