El-Husseiny, O.M., M.O. Abd-Elsamee, I.I. Omara, and A.M. Fouad. “Effect of Dietary Zinc and Niacin on Laying Hens Performance and Egg Quality”. International Journal of Poultry Science 7, no. 8 (July 15, 2008): 757–764. Accessed September 21, 2025. https://ijpsjournal.org/index.php/ijps/article/view/1028.