If the fence is made of chicken ire it can be bent into an l shape which goes into the soil.
How to keep neighbor dogs from digging under fence.
If you know anyone who can give you large rocks you could line your side of the fence with the large rocks and push any into the holes they dig.
Second place barriers to keep the dog away.
The chicken wire provides a shield which will prevent your dog from digging through under the fence successfully.
You can stop your dog from digging under the fence through redirecting to a sandbox placing chicken wire under the fence hammering another fence layer into the ground or decorate your yard with dog friendly bushes or heavy stones.
Chicken wire can be dug into the soil under the fence up to an estimated 2 feet.
Your dog will stop digging in that spot since they don t want to paw through their own droppings.
For a bigger dog you may go with a foot apart or more.
The best way to keep a neighbor s dog off your property is for your neighbors to keep their dog off.
Big jars of red pepper flakes from the dollar store might deter them a bit.
If you can t find an agreeable solution with your neighbors then you can have several other steps you can take.
Installing a chicken wire under the fence.
Determine how far apart your spikes rods etc need to be to prevent the specific animal from passing through.
Collect your dog s droppings from around your yard and place them in common spots where they tend to dig.
But you would have to replace them after every good rain.
First eliminate attractions to the dog to your yard.