John Hakari trained his young border collie Rosie to retrieve her deaf older collie sister Leia from the outdoors whenever needed and upon command. Because Leia likes to sleep outdoors, someone must rouse her and show her the way. Rosie was promised a walk in exchange for retrieving Leia, and the clever dog delivered.
My old, deaf dog likes to sleep outside. Because she’s deaf, we can’t call for her, and I don’t feel like going out to get her in the cold/snow. So we taught our younger dog to go get her. … We said it once, she did it, we praised/rewarded, and she now does it on command.