Mahmoud , U.T., O.A. Amen, T.J. Applegate, and H.W. Cheng. 2017. “Brazilian Propolis Effects on Growth, Productivity Performance, Gut Characteristics and Physiological Changes in Broiler Chickens”. International Journal of Poultry Science 16 (5): 169–179. https://doi.org/10.3923/ijps.2017.169.179.