Cover the cage so your dog cannot see out, or close the door to the room the cage is in. Your dog cannot see this correction, only hear. Bang your hand on top of the cage, the wall in the room, or the door to the room, very loud, while at the same time saying your "No" word, very loudly. Again, your dog should not see you doing this, only hear. Do it multiple times if you have to, it will stop the behavior.