Fairly common for a dog to guard their resources as you describe. Keeping them separate is the best way to keep everyone safe. You could work on counterconditioning your dog to visitors by feeding treats and have fun things for your dog only when you have visiting dogs. Consult with... more
depending on your area, anywhere from $50 to $80 for 4 visits per day.
Full medical work up and then re-start training. Might also watch dog's other behavior to find the root cause. Did something happen in the backyard? Trainer may be able to help solve the issue.
start slowly having strangers and visitors offer treats and toys. the association will develop that new people mean good things. you should consult a trainer and behaviorist for a fully developed plan to manage the emotions and train alternative behaviors.
Puppy pads are your best option. Put him on the pad and cue him to 'go potty'. If he does, lots of love and treats. Once he is trained to pad, move a soiled pad outside and continue to move him to pad, cue, and treat. Eventually the pad outside... more
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