Chicken Interferon-Beta (IFN-β) is a type I interferon produced primarily by virus-infected epithelial cells, fibroblasts, macrophages, and dendritic-like cells in chickens (Gallus gallus), where it serves as a key early mediator of innate antiviral immunity. Following recognition of viral RNA or DNA by pattern recognition receptors such as MDA5 and TLRs (notably TLR3 and TLR7, as chickens lack RIG-I), IFN-β is rapidly induced and signals through the avian type I interferon receptor complex (IFNAR1/IFNAR2), activating JAK/STAT pathways and promoting expression of interferon-stimulated genes (ISGs) that inhibit viral replication, enhance antigen presentation, and stimulate antiviral effector functions. Chicken IFN-β plays a critical role in host defense against economically important viral pathogens including avian influenza virus (AIV), Newcastle disease virus (NDV), infectious bronchitis virus (IBV), infectious bursal disease virus (IBDV), and Marek’s disease virus (MDV). Viral modulation or suppression of IFN-β signaling can influence viral replication, transmission, and disease severity. As both a biomarker and functional mediator of antiviral responses, chicken IFN-β is central to poultry immunology research, vaccine development, genetic selection for disease resistance, and studies of host–virus interactions, contributing to improved flock health and providing comparative insight into type I interferon biology in avian species.