The influence of source and level of inclusion of raw glycerin in the diet on growth performance, digestive traits, total tract apparent retention and apparent ileal digestibility of nutrients was studied in broilers from 1 to 21 days of age. The experiment was a 2 × 4 factorial with two sources of glycerin and four levels of inclusion (2.5, 5.0, 7.5, and 10%). The glycerin sources contained 87.5 or 81.6% glycerol. Study results indicated that the feed conversion utilization, and apparent ileal digestibility of dry matter and gross energy were significantly increased as the glycerin content of the diet increased while average daily gain was not affected. The researchers concluded that raw glycerin from the biodiesel industry can be used efficiently, up to 10% of the diet, as a source of energy for broilers from 1 to 21 days of age and that the energy content of well-processed raw glycerin depends primarily on its glycerol content.