Chicken gastrointestinal tract is an important site of immune cell development that not only regulates gut microbiota but also maintains extra-intestinal immunity. Recent studies have emphasized the important roles of gut microbiota in shaping immunity against
viral diseases in chicken. Microbial diversity and its integrity are the key elements for deriving immunity against invading viral pathogens. Commensal bacteria provide protection against pathogens through direct competition and by the production of
antibodies and activation of different
cytokines to modulate innate and adaptive immune responses. There are few economically important
viral diseases of chicken that perturb the intestinal microbiota diversity. Disruption of microbial homeostasis (
dysbiosis) associates with a variety of pathological states, which facilitate the establishment of acute
viral infections in chickens. In this review, we summarize the calibrated interactions among the microbiota mediated immune modulation through the production of different
interferons (IFNs) ILs, and virus-specific
IgA and
IgG, and their impact on the severity of
viral infections in chickens. Here, it also shows that acute
viral infection diminishes commensal bacteria such as Lactobacillus, Bifidobacterium, Firmicutes, and Blautia spp. populations and enhances the colonization of pathobionts, including E. coli, Shigella, and Clostridial spp., in infected chickens.