Maybe pups can learn by example. We have an electric fence for Fred--oru Doodle--but haven't started training Betty on it yet. She is an about 5 month old, 13 pound Puerto Rican rescue dog-- part daschund, etc. We just bought her a collar for the fence, knowing she needs to learn to say in the yard, but just yesterday a neighbor walked by with her dogs and we were amazed to see Betty staying behind the line right along with Fred.
We have a double wide lot, so the dogs can follow walkers (from behind that electric line) for a rather long distance--but she stayed right where she should have been. It gives me hope that she will be extra easy to train on her boundaries.