To date, there is evidence that the pathological process caused by a bacterial infection initiates in poultry the expression of a number of genes including those associated with the synthesis of interleukins (IL6, IL8L2), β-defensins (AvBD9, AvBD10, AvBD11), caspase (CASP6), prostaglandin-endoperoxide synthase-2 (PTGS2) and interferon regulatory factor 7 (IRF7) and contributes to the implementation of innate immunity (e.g., Chiang et al. [88]). The gene discussed is CASP6; the disease is bacterial infectious disease.