I once worked on a property with 2 german shepherds. They were kept in a big cage in the courtyard. As soon as they heard or saw someone they would go mental, snarling, barking, throwing themselves at the cage to get out.... they were attack dogs.
Only the owner and their trainer could interact with them. If the owner died or couldnt get back to shut them away for some reason, the wife would have to call the trainer out to sort it because the dogs would attack her given the chance..... why would you???
Edit to say, only the trainer and owner could feed them, they wouldnt accept food from anyone else.