Barking

Question
I have an Australian Shepherd and he hates strangers. On walks, we've trained him not to bark or jump at strangers but when strangers come to or into our house, he barks viciously and growls. He also tries to jump at them. After a long time, he'll stop barking and calm down but if any stranger gets up or touches anything, he'll go crazy again. I've tried to train him with treats, put him in a room by himself, or scold him but he doesn't seem to care at all.

Answer
If you read the Australian Shepherd breed standard, it does say that they are dogs with "strong herding and guarding instinct" so this behavior is common in some of them.  Even some dogs that were very well socialized as puppies (20 new experiences every day throughout puppy hood, and should have met at least 100 people by age 12 weeks), develop this tendency as they mature.  Scolding has no impact, and using treats is fine, but you still need to know how to train the behavior you want.  Personally, if your dog is this upset at visitors coming, and he is growling at your guests, do NOT assume that he will always be benign.  Herding dogs that work cattle are often bred to poke or nip a recalcitrant cow, and they sometimes transfer this skill to the seat of a human's pants if we don't manage and train them to a high standard.  If this were my dog, I would just train him to wait in a kennel or another room when guests are over until you can get a good trainer (clicker training is what I prefer for these intelligent and sensitive dogs) to help you train "leave it" "stay" "come" and "down" to a level where you can control the dog around significant distraction.  If you are not inclined to do a lot of work on this, it's safer not to have him interact with your guests.