1. Preheat the oven to 400°F. Put the chicken pieces in an ovenproof dish, sprinkle with salt and pepper, and roast in the preheated oven for 30 minutes.
2. Cut the rhubarb into pieces and mix it with the sugar in a bowl. Take the chicken out of the oven, place the rhubarb under the chicken, put it back in the oven, and roast for 15 minutes more. Serve warm.