We studied the influence of cereal, heat processing of the cereal, and inclusion of additional fiber in the diet on the productive performance and digestive traits of broilers from 1 to 21 d of age. Twelve treatments were arranged factorially, with 2 cereals (corn and rice), 2 heat-processing treatments of the cereals (raw and cooked), and 3 sources of fiber (none, 3% oat hulls, and 3% soy hulls). Each treatment was replicated 6 (trial 1) or 3 (trial 2) times. Growth traits were recorded in both trials; digestive traits were measured in trial 1, and total tract apparent retention (TTAR) of nutrients was determined in trial 2. Feeding rice improved TTAR of all nutrients and feed conversion from 1 to 21 d of age (P <or= 0.001). In addition, feeding rice increased the pH of gizzard digesta (P <or= 0.001) and reduced the relative weight (RW) of most digestive organs. Heat processing had little effect on the growth or size of digestive organs but improved the TTAR of most nutrients in the corn diets. Fiber inclusion improved the TTAR of most nutrients, BW gain (P <or= 0.01), and feed conversion (P <or= 0.001) from 1 to 21 d of age. In addition, fiber inclusion increased the RW of the gizzard (P <or= 0.001), ceca (P <or= 0.05), and digestive tract (P <or= 0.01) and reduced digesta pH (P <or= 0.001) and the length of the small intestine (P <or= 0.05). The effects of hulls on RW of the gizzard and on the TTAR were more pronounced for the rice diets than for the corn diets. We concluded that rice can be used successfully in broiler diets and that heat processing of the cereal does not have any beneficial effect on broiler performance. The inclusion of moderate amounts of fiber in low-fiber diets might improve chick performance at early ages by reducing gizzard pH and improving the utilization of nutrients. Therefore, young broiler chicks might require a minimal amount of fiber in the diet.