I think our new dog, Hailey, is dog selective, or dog agressive. I'm still trying to figure out which. The previous owner's reason for sending her to the humane society was that their other dog was mean to her, so maybe that has something to do with it. Hailey loves Molly, they are the best of friends. But any time she sees another dog she growls, then barks a lot and lunges toward it. She doesn't listen to me, I have to drag her away I have no experience with a dog who is so agressive towards other dogs. How can I help her?