Have you guys considered letting the dogs live in the house? This way they can be better monitered and seperated. How old is the puppy? I'm assuming the pen is big enough to accomodate 2 dogs, but you also have to consider that every time they turn around, there is the other and they really have no escape from each other except the other side of the pen (and who wouldn't want an escape from a puppy?). In the house they would be able to go to another room or a crate and there would be less tension. Shelby has a young intruder in her space and while for now it's just scuffles for food, it could turn into fights for space.


If they must continue to live in the pen, then the above suggestions are going to be your best bet. But IMO they would both be happier being in the house with the rest of their "pack", you and your brother. Right now, Shelby is the alpha making up her own rules, you are just the bringer of food. If they lived inside, they would learn that you and your brother are the "alpha dogs" and your rules are the ones that apply.