I have found a good method of keeping a dog from digging under a fence. You purchase chicken wire and attach one edge to the fence at the bottom with staples if wood and ties if chainlink. You then bend it so the chicken wire lies on the ground around the perimeter. You can bury it with a thin layer of dirt or let the grass grow through it. Either way, a dog does not like the feel of the chicken wire on his nails and is unable to dig out.
A more practical and nicer looking solution in my opinion is installing an electric wire around the perimeter of the property similar to what they use for horses and cows but a much smaller voltage. This physically keeps the dog away from the fence so they can not dig under or even get close to the fence to climb over or destroy it.
They make plastic holders for the wire that attach to chain link. You can run one close to the top of the fence if a dog is jumping over and / or one about 6 inches or so from the bottom. You can also string 2 or 3 wires along a fence. One controller should power both wires. They do shock, but I can assure you that it is not a bad shock as I personally touched it and got shocked before I would allow it to be used for my rotties. It only took my dogs getting shocked once each to learn to stay away from the wire. My dogs would pull the chain link off the bottom rail of their kennel and fencing too. I used this and it solved the problem.. The following site has the main unit though the next site sells complete kits. Lowes and tractor supply stores sell these as should any feed type store.
Of course you could also use shock collars and underground fence as well . For one dog, the cost would be about the same or even cheaper if you bought a used system. However, the batteries in the collar can be depleated and need to be replaced. With a hot wire style fence, as long as it has electricity, it is working. I use the hot wire type for my rotties. It works well. I think it will be a good choice, but the ultimate decision is yours.
I hope this information is helpful to you and you are satisfied with my response. If you would like any additional information or have more questions please don’t hesitate to press the reply to expert or continue conversation button so I can address any issues you still have .
BTW, how does the collar works? does it give the dog a shock evry time he tried to break out?