so... my sweet CC just got 1 year old: the very next day he almost jumped off the fence to grab a staffy and rip his head off. That staffy is an unstable dog and we knew it. Still, Jack didn't seem to have a problem with him before. The staffy was on the street (alone), jumping up and down our fence, so jack climbed on the other side of the fence and tried to grab the dog by the head. I pulled Jack back by the collar and he turned his head half way towards my hand and snapped (he didn't touch the skin). The hysterical staffy was still there barking at us. I can't control the dogs on the street, but I was always able to control mine - now it seems that he becomes more protective/aggressive towards male dogs and me getting in the middle is not a good idea anymore. I am not worried about front yard - I will not let him there until I put proper fences in place. I am worried it can happen at the dog park/during walks or in any other place. Should I get a muzzle for him? Training? He's obedient - except that moment when he was in attack mood. I do work with him basic obedience daily, he's good. I somehow expected him to mature, but I didn't see it coming so soon and so strong. May the 2 puppies contribute to his aggressiveness - he feels the need to protect the pups? What would be the best approach, before it escalates?