Marley's Boyfriend, Diesel

My friend Alex got a blue nose Pit Bull puppy about a month before I got Marley. He named him Diesel, and let me tell you, Diesel is a monster pup. For only being four months old Diesel weighs a little over 20 pounds. Diesel is a beautiful blue nose pit and comes from a prime bloodline of blue nose pits. Alex and I have been discussing with each about breeding Marley and Diesel since they both are beautiful dogs and both are full breed pit. The third week I had Marley, I went over to Alex's apartment and brought Marley with me. Diesel and Marley began to play with each other but at this time Diesel was three times the size of Marley. After a few minutes of playing Diesel was beginning to pick on her by holding her down with his huge paws, this was the first time I had ever seen Marley react the way she did. She snapped at him and then showed her teeth for intimidation. We broke them up after that and I then left. About a week ago I took Marley out on the quad for a walk and Alex brought Diesel with him. They both just played with each other while a large group of girls surrounded them telling us both how cute they are. Alex and I both have been saving up to build a kennel at his home in Canton, OH. I am going to get her papers so that we have two parents with papers, making the puppies worth more money. If we are able to do this right, and are able to have a healthy litter produced we could sell each puppy for up too 400-500 dollars a piece.