Dr Hosna Hajati is a Postdoctoral Fellow in Poultry Nutrition in the Department of Animal Science of the University of Tehran, Iran. She received her PhD from Ferdowsi University of Mashhad, Iran. Her research interest areas are natural feed additives, in ovo feeding, and the nutrition game birds. Her publications include five articles in domestic journals and six books. Dr Mojtaba Zaghari, PhD, is Professor in Poultry Nutrition in the Department of Animal Science of the University of Tehran, Iran. He has published more than 142 peer-reviewed papers, and is a member of the editorial board of Journal of Livestock Science and Technologies and Iranian Journal of Animal Science. He is also a member of the Academy of Science of Iran and the Technical Advisory Group on Feed Additives at the Food and Agriculture Organization of the United Nations. He has extensive experience in using feed additives in poultry nutrition and metabolic disorders in breeder hens.