ALhammadi, Mohammed Ali2022-05-182022-05-1820021956https://drepo.sdl.edu.sa/handle/20.500.14154/3695This research aims to study Marek’s disease in Al-Ahsa province, Eastern region, of Saudi Arabia, where in this study was the first case isolate and the definition of a disease that affects poultry. The questionnaire survey was conducted on 48 poultry farms (broilers and layers) to collect information on prevalence and importance of this disease in the region.enThesis