I inherited a 5 year old Australian Shepherd a few months back. Every time we go outside he gets out in front of my other 2 dogs and tries to herd them together.At first it was amusing, but now he's getting real aggressive. He runs at the other two, growling and nipping them until they get behind me for protection. But even that doesn't work too well. I'm guessing that it's a trait, bred into them so that they make good herders. And I don't mind that. I do mind that my other dogs are afraid to go outside without me. I live in the country, and they all have access to go in and out at their convenience. I don't know if it matters, but until I got the dog, he was always an inside dog. Please, any help or ideas would be appreciated. Thank you.