It depends on what you mean by hurt. The dog gets a small shock, which doesn't feel good, so you could call this hurt. However, the dog doesn't suffer any lasting damage from the invisible fence.
there is a cable line underground, and when the animal passes the cable the animals collar is triggered and shocks the pet. I don't know if I'm wrong, but I think that's how it works.
You need a post hole digger and cement. YOu have to measure out the area that you are putting the post. YOu can space them apart every 6-8 feet. You dig the hole and have the cement prepared and when...