Ashley I can relate to this. This is the exact reason why I joined PT, Sadie and Maggie were fighting. They still get into little scraps now and then, and same as you, food is not involved. It seems to be a dominance issue like you said. The only thing I can say is to keep reinforcing Shadow as alpha and just keep an eye on her and Mini. It's to the point with me that I can see when they are about to go at it and I tell them to quit and stand right by them and make them go away from each other. Mini is a female, right? Here is the link to my original post and maybe it can help some. Hope it all works out for you.