Chickens gut have diverse and complex microbial agents that have a critical function in digestability, nutrients uptake, development of immunity and pathogen fight. Then, gut health and bird productivty performance have been linked to falctuation in the intestinal microbiome components.  Nevertheless, many factors affect the functionality, integrity and health of the bird's gut including the circumestannces, ration, and the intestinal microbiota. Pathogenesis of enteric and non intestinal illness may result in disturbances in the gut ecosystem; dysbiosis. Gumboro disease is a serious and infectious viral disease that affects chicks and is linked to significant morbidity and mortality rates. The bursa of fabrecius is the target organ of this immunosuppressive virus. Infectious bursal disease (IBD) virus causes histological lesions, alterations in immune cells, and changes in the microbial population by reproducing in gut-associated lymphoid tissue. Our review as part of Master's degree in poultry diseases, mainly focuses on the collection of published data the role of chicken microbiota in gut health, host immunity and chicken productivity in addition to factors affecting microbiota as age, sex, breed, maternal antibody, season, ration composition, antibiotics, relation between pathogen and intestinal microbiota with special reference to effect of IBD on gut microbiota ecosystem with role of probiotic and prebiotic in correction of dysbiosis.