1 year old male suddenly dog aggression
My rough collie intact boy has just turned 1 and is generally very sweet, calm and gentle. He does experience some reactivity towards bikes/runners/people behaving strangely etc but we are working on this and it tends to just manifest in barking and lunging sometimes. He hasn't experienced any dog reactivity, he is actually regularly praised on how gentle and respectful he is with dogs. When reactive dogs we pass have barked at him he has always ignored it and carried on with his walk.
Today however we met two boxers on a very narrow path, they barked quite aggressively from a distance but the owner kept striding forward so I (stupidly) thought they must just be very vocal, all the dogs were on the lead. When we got closer they were lunging so I pulled my dog to the side, the man did the same and asked me to pass by him. I took my dog by the collar to just get passed quickly but suddenly my dog started growling, lunging and barking at them, because I was restraining him, he started to redirect onto me. Once we got past, the man struggled to pull the boxers away and they kept pulling towards my dog, barking. My dog recovered quickly and on the same narrow path bumped into 3 more dogs 30 seconds later who he was very happy, calm and social with - as normal.
I bumped into the guy out in the open and pulled my dog away quickly, before he started barking properly. I apologised to the man, who said not to worry and it was probably because he had two dogs, they were all on the lead and my dog probably just wanted to protect me. Upon reflection I think I only apologised to start a conversation, hoping he would tell me his dogs were just very dog reactive and that must have sparked it, but he didn't.
I am so shaken by all of this. My boy is large and he was a handful, especially when he started redirecting. I don't know if this could be the beginning of dog reactivity or if my dog simply felt trapped on a narrow path and these two dogs gave off particularly aggressive body language. It was obvious that the boxers were reactive but I ended up worrying my boy did something wrong even though he only gave back what they gave him. We haven't had any altercations with dogs before, apart from a couple of (fairly polite) corrections both given and received. I was wondering if anyone has any better insight into this?