Ball pythons are ambush hunters and need to feel secure to eat. Some will sit in their hides in ambush mode with head sticking out. If they feel vulnerable or insecure they wont be intersted in eating. Try leaving the rat in the room with snake 15-20 minutes before introducing him in the tank. The snake will smell him and should go into feed mode if hungry. You also have to make sure your temps and humidity are correct because a cool dry snake wont be too hungry either. Hope this is helpful.