I'm looking for a bit of advice on my dog Max. Max is a 2yr old collie cross that I adopted 5 weeks ago from a dog shelter, he is walking a good heel until we see other dogs, when he lunges, even from a distance,this is a problem as he is a big dog 40 kilos , and actualy managed to pull me over, Then set off after the dog, because of this I'm trying to avoid these situations.
Also in the car and from the balcony, if he see's other dogs he barks and growls,with hackles up.
How can I go about safely socializing him with other dogs?
Yesterday he also lunged barking towards a person as we passed, although he has shown no other signs of aggression towards people
What should I do about that?