One of my dogs, Moose, is a wandering Black Labrador; the other dog, Heidi, is an Australian Shepherd who never left the yard until he showed up! My son left the screen door open at night and the dogs left together, somehow crossing a busy highway – I don’t know how they did it. A dog lover found them and took them to a vet to be scanned and we were able to get them back through PetLink.