The effects of dietary β-glucans on chickens from 3 distinct genetic lines were measured from weeks 3 through 8 of age. At 8 weeks of age, broilers fed the β-glucan diet had a higher breast-to-body-weight ratio than those fed the control diet, without a difference in feed efficiency. Evaluation of the effect of β-glucans as dietary supplements is important to determine the benefits of their utilization in poultry diets.