1. Preheat oven to 325 degrees Fahrenheit.
2. Pour the oil into the bottom of a baking dish. Slice the yams and place on top. Add the prunes. Pour orange juice into the pan.
3. Place chicken on top. Rub with white wine sauce.
4. Cover with a piece of parchment paper that fits within the pan, and then cover very well with foil.
5. Bake for two and a half hours, uncovering for the last 15 minutes.