This way they get the rollers higher and motivate them. After a certain height they also start tumbling. Some times they are raised just as a highflying breed. In reality Bongo is the Turkish word for Owl. I have never seen one tumble and never heard from any body that they do.
Color is secondary in importance.
The most important feature is the shape of the head. Eyes have to in a way pop out as much as possible from the head. Beak has to be as small as possible. Head has to be big and square.