My dog is the tallest dog who lives in the house, and yet is bullied by the bitch, who has lately been really nasty to him. SHE wont let him out of the garden, if he goes out there she goes for him. When the post comes she blames him for it, and goes for him. If he is playing with the other dog she goes for him. He also allows the smaller dog to growl and snap at him, if he plays with a toy that takes the smaller dogs fancy the smaller dog will growl and snap until he leaves it alone. The reason i am saying this is because no matte rhow much he surrenders to the dogs he live with he is awfully terrible with stranger dogs: HE kind of puts on this face of " Im really strong and could beat you up anyday" and goes for the dogs at any thing thy do that he does not like them doing. i.e chasing there ball. He attacks in  a simmilar manner to the way he gets atacked. But he does agility, and has gone at three dogs, one for doing a collie stare at him- understandable- ther other because i threw his ball near the dog and he probly thought the dog was attemting to nic the ball, and the other for chewing his ball.
Does anybody have any ideas of why he is aggressive to other stranger dogs, and how i could stop him beign aggressive to stranger dogs.
Please help xx