Need Help Predator Proofing !!

I need help with predator proofing my coop and run. Something dug into one of my chicken pens at night and got all 8 Lavender Orps. First time we have had a problem but I figure they will be back. Lots of questions and in desperate need for answers before they strike again. The first coop I am fixing is an open coop. It is walled up on 3 sides and then open into the run which is 2x4 welded wire.
1. Can I use the 2x4 welded wire around the bottom of the run?
2. How far out should I run the wire? I was thinking 2 feet. Do I bury the wire?
3. Should I run it inside the pen a foot or so? Or can I bend the wire up inside the pen and wire it to the pens wire about 4-6 inches up?
4. Can I use the 2x4 welded wire over the top of the run? It will attach to the open side of the coop and cover the run so there will be no openings.

2nd Coop 10x10 dog run (chain link fencing) This is where I plan to put my silkies. Was going to use the 2x4 welded wire about 2 foot out all the way around.Then I am going to put hardware cloth all the way around about 3ft up. Going to build a coop for the silkies 3'Wx8'Lx4'H with a floor in it. It will be totally enclosed and locked at night.

Any advice would be greatly appreciated. Right now I have a baby monitor set up in the coop so I can monitor the sounds all night. Also have a game camera set up to try and see what may be visiting my coop. If something did get in the coop and start getting the chickens would they start squawking. I am hoping it will wake me up.
My chickens free range all day and I've only lost 2.

How big was the hole that was dug? Was it right under the fence, or tunneled? Did it carry off everything, or just wreak havoc and run?

For starters, I've found the best defense against a ground predator that likes to dig is a low-impedance electric fence set a few inches off the ground just outside the fence of your run. Getting a small jolt to the nose seems to discourage most dog-related animals and actually train them to avoid the area even after the electric fence is removed. You will need a controller, some wire, and some insulators (along with stakes if you cannot attach the plastic insulators directly to your run).

http://www.tractorsupply.com/zareba-reg-2-mile-ac-low-impedance-fence-charger-1026380

For predators that are smarter than the electric fence, you can dig a narrow trench (a few inches is sufficient) along the bottom of your fenceline. Mix up some quickcrete and fill the trench, anchoring your fence in the concrete. This is not as expensive as you would think as long as your trench stays fairly narrow, but it will need to be at least as deep as the hole dug previously.

Also, if the hole dug is not very large, you may consider going on the offensive with a catch-and-release style trap. These come in various sizes and prices, but include the choice of what to do with the predator once you've caught it.

http://www.tractorsupply.com/catch-and-release-live-animal-trap-pack-of-2-5132129

My last choice option would be to wire the floor of my run. Not only does this limit my flock's ability to scratch and dirtbathe, but fence materials do not last long when in direct contact with the ground.

I have chain link on my runs. I also used the chain link as the apron. Over the chain link I've put 1/2" welded wire 2 feet out from the bottom and 3 ft. up. This takes care of small and large predators.
I'd put wire and also stack some rock along the outside if I were you. Whatever you've got it's tenacious! If I had electricity to my coops I'd definitely use an electric wire. Lots of different ways to approach it, but use more than just one defense. Then at least you'll be able to see when something is trying to get in. Check the perimeter of you coop/run daily. Sorry you lost so many beautiful birds.

Thanks so much for the advice.