Preheat oven to 350ºF. Wash potatoes and cut into ½ inch dice. Clean and cut mushrooms in half. Cut bacon into small dice. Peel onions and keep whole (or use frozen ones). Clean and season chicken with salt and pepper. Place chicken in 8-inch pans. Add the potatoes, mushrooms, bacon and onion to roasting pan. Pour the oil on top and dot with butter. Bake for 45 minutes. Remove from oven and pour wine into pan. Return to oven and cook for an additional 15-20 minutes.