Q. Our 6-year-old Sheltie is a great dog in many ways. He’s timid, but adjusts well with a little time. However, we have a problem with incessant barking. This happens even with people he knows well.

Q: A relative has a sheltie who barks. It doesn’t matter if someone is coming or going. Rebel does not run to greet the visitor and he doesn’t try to go outside. Quite simply, the sound of the door ...