How do I get my 3 month old puppy to stop hassling my 12 year old dog?

I have 3 dogs. An 11yr old Cattle x Kelpie named Crystal, A 12 yr old Maltese Terrier named Bobby and a 3 month old Border Collie x Foxy puppy named Saffron (I know she is a weird breed) Well anyway Crystal is the alpha, but somehow Saffron is above Bobby, even though Bobby is bigger than her. When we are not... show more I have 3 dogs. An 11yr old Cattle x Kelpie named Crystal, A 12 yr old Maltese Terrier named Bobby and a 3 month old Border Collie x Foxy puppy named Saffron (I know she is a weird breed)
Well anyway Crystal is the alpha, but somehow Saffron is above Bobby, even though Bobby is bigger than her. When we are not around she bites and hassles Bobby all the time, but he is too much of a coward to stand up to her and he just takes everything. Saffron knows she can overpower him without him getting angry and biting back, how do I stop her from hassling him all the time?
Update: I can't get another puppy, she was my Christmas present and my mother would think I don't appreciate her.
7 answers 7