I'll try to make this back story as short as possible. We adopted Barrett at six months old. I made sure to show him my dominance and he never questioned it. As long as my husband or I brought someone into the house he was perfectly fine and never reacted aggressively. Out of the home he never even barked at people just out of the blue but would occasionally bark at people when they would try to pet him. I generally just didn't allow people he didn't know to pet him and called it a day. About seven months ago me and my husband decided to end our marriage. I gave Barrett to him and I took the rest of the pets, it broke my heart but it was for the best. My husband ended up moving into an apartment and with him being in the military and gone a lot he had no one to watch Barrett. So in October of last year he decided that the best thing for Barrett was to have his mother take him until he was in a better position. My husband and I have since worked out our issues and decided to stay together. We haven't been in the position to get Barrett back until now. We're moving closer to his mother and will be able to have our boy back in less than two months. Here's the issue. Since Barrett has been living with my in laws he has developed aggression whenever people come to the door or into the house. It's not everyone but it's a mix of people with no common traits. He does his "Big boy growl" and has taken it as far as snapping at people. My plan so far has been to reinforce that I am the alpha and that it is my job to pick who is okay to come into the house and who isn't. I plan on having strangers come to the house and having Barrett on a leash in a laying position by my side. I want them to ignore him as long as he is reactive then once he is calm have them start by tossing him treats from a distance eventually getting to the point where they can hand him treats as long as he remains nonreactive. He is my first GSD and I'm not sure if this is the best course of action and wanted to get more experienced owners opinion of what I should prepare to do when we get him back.