Fear-based aggression + redirected aggression in dogs

Hello everyone! A question for the experts. I'm a dog trainer myself and have just encountered a serious case, and I'm interested in the opinions of other experts. We have a two-year-old Jack Russell who is aggressive toward his owner, his entire family, and anyone who even pays attention to him or wants anything from him. He's calmer outside, but in the apartment, his owner can easily wash his paws, put his collar on, and so on. His arms are covered in bite scars. It's clear he's stressed before the bite, hovering over himself and showing warning signs like baring his teeth and growling, although sometimes they're too fleeting to notice. According to his owner, he was very much loved. It all started at seven months old, when the dog was lying on the floor and his owner bent down to grab something, the dog lunged and bit her cheek. The dog was fried for this, and after that, incidents started popping up here and there. Afterward, my husband started training dogs, but not properly. He would pin the dog to the ground, bully it, and hit it. This could last for half an hour, which only escalated the aggression. But that wasn't the initial trigger!

The dog now genuinely distrusts people and doesn't read intentions. If a person sitting on the couch reaches for the TV remote, for example, the dog might react to the hand movement and attack, even though it had previously been relatively normal. The dog can also easily switch to its owner, even if the initial stimulus was another person. In other words, the dog doesn't know how or understand how to relieve tension other than by biting.

My plan for dealing with this situation is to establish contact, communicate with the owner, establish house rules, hand-feed the dog, walk the dog on a leash around the house so I can always control the dog and avoid being afraid of bites so as not to aggravate the situation with my fear, and train the dog to wear a muzzle for safety. However, I'm not sure which method or exercise is best to teach the dog to switch off and relieve stress during aggressive behavior, since under such stress, food and toys don't react. I'm not sure about using an aversive, as I don't want to confirm the dog's thoughts that people are bad and painful. On the other hand, I need to explain to the dog that attacking people is bad and have a way to turn the dog off and redirect it to a positive state. I usually do this with a prong collar, but I'm really unsure right now. So, what advice can you give me besides working with food, contact, trust, and training to recognize body language, especially in tense moments? For example, when a dog tries to assert itself and lunges, in this case, at my grandmother, who is the weakest and most insecure member of the family. Incidentally, a dog can also approach me on its own, asking to be petted, but after a few minutes, start growling and lunging. I've advised the owner to watch her body language and stop petting the dog at the first sign of a growl or a snarl. But the very fact of this behavior is strange. I think it's an innately unstable temperament due to poor breeding, and my husband's attempt to correct this behavior has greatly exacerbated it.

#dagtraining, #dog, #agression, #askdog