Highly pathogenic avian influenza (HPAI) affects chicken production not only during outbreaks but also afterward. Understanding its delayed effect is essential for facilitating timely production recovery. Employing a dynamic panel data model with annual Chinese provincial data obtained between 2004 and 2021, we quantified the impact of previous-year HPAI outbreaks on current-year chicken production through production costs. The results indicated that a 1% increase in provincial HPAI outbreaks raised production costs per 100 broilers by 0.372%, ultimately reducing annual chicken production by 0.038%. These findings remained robust after controlling for endogeneity and conducting extensive robustness checks. The impact was most pronounced in provinces characterized by high chicken production, a high proportion of scale broilers, and yellow-feathered broiler specialization, where both production costs and production losses were significantly greater. Additionally, previous-year HPAI outbreaks significantly increased production costs by increasing both epidemic prevention and broiler chick costs. Our findings offer robust empirical evidence and actionable insights for managing cost volatility risks along the chicken supply chain in post-epidemic contexts.