I have a german shepherd I acquired about 2 months ago as a stray and he is an outside dog. He has recently become aggressive to strangers that come in the yard, but only if one of the family members goes out into the yard as well. If family stays inside, he will let stranger approach door, knock and come in. How should I handle this in the best way for all of us? He also chases the stranger's vehicle down the driveway when they leave, barking aggressively and nipping at tires. He does not do this to family members' vehicles. How do I stop this behavior as I am afraid he is going to bite someone.
Do you have a backyard you can put the dog in when he acts up? Its important to correct him as soon as he shows this behaviour. When he starts barking or harrassing visitors, get to the yard, tell him "no", and then remove him from the area. Tie him up or put him in the backyard. You need to correct him EVERY time and as soon as he begins this bad behaviour.
My own dog used to bark at anyone coming to our gate or going past it, except people who lived at the house. Any time I heard him bark, I gunned it to the front yard, told him "NO" (very sternly!), and got him by the collar, tied him up in the back yard, and left him there for a while to cool off. He got the point pretty quickly.
You should also work on your dog being in the same space as you and strangers, because his behaviour is a bit indicative of protective aggression, since it worsens when you are in the area. Does he show any kind of this behaviour when you walk him, or is it just when he's in "his territory"? Try having friends come over and test out his reactions, if he goes berserk, correct him and remove him for a few minutes to calm down. Then bring him back to the yard with the visitor, on a lead, and speak to the visitor, ignoring your dog. Let him get comfortable with a new person in the yard, ask your friend not to interact with the dog at all, but to continue talking happily to you. Your attitude and tone are important, you want to convey that the visitor is a good thing to your dog. If he absolutely cant calm down, try removing him for 10 minutes and trying again.
I hope these suggestions help. You might also try enrolling in an obedience course or puppy class, both to socialize him and to train him to listen to you and obey. German Shepherds are very intelligent, so an obedience course should go smoothly, and be fun for him, I really recommend classes as a great way to bond with your dog and have a good time learning how to manage them
Please keep us updated on how things go, we can always offer more suggestions and help if this doesn't help you
