Traditional healing and rituals.
Yes, these work I hear, well, when it comes to inviting evil spirits into your body to grant you ecstacy, you will forth at the mouth once cleansed by these healers. I put it down to certain secret societies that want to cover these things up for their own agendas that they are not researched, but, I am here now to validate these rituals for us.
So, let's start with chicken bones? The reason chicken bones are used is because they are light an give depth to the questions. When someone thinks of an issue, it creates an aura or emotional energy that will manifest in the 'aura of the heat' the person gives off. This is where the energies coming from the feeling of someone would emanate into the bones, the way you throw the bones, the energy coming from 'guilt' and fear - as people often have a premonition to the questions - and then other factors too. The voice of the question asker would affect the determined aspect of the throw too.
Then there is 'texture of the floor for them to roll on.' This would show how many times they roll, being where the floor used is showing that dents would be familiar to the sangoma or witch doctor, where they are used to seeing the same queries.
But more the throw. The throw of the bones is where the witch doctor would have energy coming into them from the feeling of the throw, where the energy and heat they are feeling from the seeker would affect the way their muscles respond to the whole affair. This would be where the 'event' would would affect the throw, the time would affect the amount of energy in the witch doctor and query, where breakfast is far away and lunch is soon, so as to allow for the hunger to affect the throws, and so forth.
Through trial and error, like questioning a lecturer, we can find patterns in the cosmos, and, the answers we seek.