Our puppy is 11mo old and we think a Dutch or German shepherd mix (got him from a local rescue at 10wks). We got behind on socializing him as he fractured a leg and then a toe in back to back succession the first few months of having him. We had to keep him crated and couldn't take him anywhere. Once he had fully healed, we then had to wait longer while we got him his shots (vets in our area were swamped and overbooked, including the one who had been seeing him for his fractures). By the time he was healed and ready to go around people and dogs, he was considerably older than we would have liked. However, we have a 2yr old rescue dog and 4 cats that the puppy loves, so we figured it wouldn't be a problem.

Well, obviously we were wrong if I'm here.

We took him to a local dog park that was slow that day, only one other dog there apart from his brother. He was really growly and barky thru the fence, but we let him sniff and meet them and see his brother playing with them to no issue. When he had calmed down, we let him in, but he chased after the other dog barking. I was able to recall him off and held him with me the 20min we stayed, but he would get growly and nippy if the other dog got close to check him out. So, we decided dog parks were off limits until we could ensure other dogs wouldn't be at risk.

We visited a friend for a Thanksgiving party and took our dogs cause they both love people. One of the people there had brought there German shepherd puppy who was about 13mo old. Our puppy immediately got barky and growly upon seeing her. We slowly let them sniff each other, but he tried nipping. At one point her parents weren't paying attention and she came over and sort of crowded his space, which resulted in a tussle and him biting her. He didn't break skin and it seemed like a warning bite, so we kept them separate the rest of the night. Eventually he got to where he could have her within a few feet of her, but would growl or nip if she got too close. They did end up sleeping near each other while we hung out, so that was nice.

Recently, we were walking around our neighborhood with him and his brother, and we passed by a house that we knew had other dogs. They saw us coming and brought theirs in since they don't have a fence, so that was nice. We finish most our walk, and ended up circling back by their house. Turns out they were in the driveway and had one of their dogs with them. Their dog saw us and left their yard and crossed the street to see us. We tried calling out to the people to recall their dog, and they saw us, but did nothing. Their dog seemed friendly enough and our other dog is friendly, so we let them greet. Our puppy though was losing his mind. He was using his big bark (not playing one) and had his hackles up and was lunging towards the other dog and biting the air. I kept trying to lead him away and recall him, and he was frantic trying to respond to me and jumping towards me (which he never does) then back towards the other dog. The other dog started approaching us and I couldn't back up fast enough and tripped and fell. Luckily the dog stopped to mark something and we were able to leave, the other owners allowed their dog to continue following us for a bit and our puppy kept shooting glances back but has finished the barking and growling with distance placed.

All this to say, we are worried for him. I think it is a fear response. He only has issue with dogs his size or bigger. He has met smaller dogs my family owns and can be around him off leash and without worry. He loves our cats and his dog brother, who is his size. There is a house near us with two German shepherds they keep in their fenced in yard. When we walk by they go nuts barking, but our puppy will go by without care apart from curiosity, even when we walk within 5ft of the chainlink fence. When we walk nearby trails, he will pull to get close to dogs passing, but he doesn't growl or raise his hackles.

He has had a similar barking and growling response (never lunging or biting) to meet people who look different than he's used (men with large beards, black people, very tall people), but has calmed down with exposure.

Any help will be useful! He is a very smart boy and knows all the basic tricks and a handful more. He is very food and play (fetch particularly) motivated, so training him is a breeze. I know he might never be a fan of other dogs, but I would like to not have to worry about it in the future if I could make him less reactive. I really think it's a fear response, I just don't know how to expose him without risking other dogs.