Chain Link Fence

Combined with e-fence...welded or chainlink should be fine. Chainlink is pretty solid especially if you secure it well at the bottom and top depending on how you have it now. The e-fence will teach a dog real fast LOL!

 

Some dogs are so determined they will eat the fence, as you see. How big of an area are you fencing? I wouldn't cattle panel my whole back yard, but I use them on my chicken's run to support the welded wire that holds the chickens in and keeps raccoons out. (My nemesis is a pit bull) I'd pretty much guarantee your dogs wouldn't be able to bite through the cattle panels, they're what, 10, 8 gauge?

I also second the electric fence. Especially for a large area like a perimeter fence. They make insulated stand-offs that connect to T-posts and ones made for chainlink. E-fence will help with a lot of predators and they're relatively cheap.

 

We have a chainlink run and its done a pretty good job of keeping most of the neighbors dogs out (none of them are St. Benard sized). The only problem we've had was one of our neighbors dogs was a climber. He climbed right to the top and over that 6 foot tall fence. And sadly sealed his fate when he wasn't smart enough to climb back out. We skirted ours with hardware cloth around the bottom. I have been considering putting an electric fence around it as well, but we haven't seen anymore amazing fence climbing dogs for a while so it hasn't been our first priority. Good luck!

 

I would do a couple of strands of electric. 12'x12' isn't all that big so it can be relatively inexpensive. I'd put it a 2-3" up, and, I'm not sure how much farther since you're dealing with a St. Bernard... whatever "sniffing height" might be for him. They learn real quick. I have electric fencing for my horses, and my dog ran under it one day, accidentally hitting it with just the tip of his tail. He's been VERY careful around the fence since then!

 

If you run electric fence you will teach the dogs to steer clear plus get the extra predator defence and maybe a really cool Youtube video!

You could go with dog kennel panels but be sure the sides and bottom edges of the wire are well fastened