Yet another reason that "electric fences" are worthless. A determined dog will forego the pain if he really really really wants to be on the other side.
Try putting up a REAL fence. That will not only keep your dogs from running off, it will also keep people (and other animals) from coming into your yard and stealing, hurting, or killing your dogs.
This happened recently not too far from me:
Officers are investigating to determine whether someone stabbed a 10-year-old Cavalier King Charles spaniel to death and then skinned it, according to a Denton County Sheriff’s Office report.
The owners said they let the dog, which was nearly deaf, out of their house — in the 700 block of Oak Shores Drive in the Cross Roads area — into the yard along with their three other dogs. The owners have an invisible electric fence that keeps the dogs in the area, they said. Later they discovered that the spaniel, “Bonny,” was missing and began to search for him.
The wife found what she believed to be the body of the dog in some nearby woods. She called for her husband, who thought wild animals had killed the dog, according to the report. He asked a family friend to bury the dog because he was too upset about losing the family pet to do it, and the friend asked if he could take the remains to a veterinarian to determine its cause of death, according to the report.
Personally, I think using pain to keep your dog confined is cruel.