Biochar in Poultry Production as a Circular Economy Strategy: Waste Valorization, Antibiotic Reduction, and Sustainability Outcomes

Intensive poultry production faces linked challenges of manure accumulation, ammonia and greenhouse gas emissions, nutrient losses, pathogen pressure, and continued antibiotic dependence. In this context, biochar (BC) offers a circular pathway that converts biomass and poultry-derived residues into a value-added material for feed supplementation, litter treatment, manure management, and nutrient recovery. This review synthesizes current evidence on the role of BC in poultry systems through an integrated circular economy and sustainability lens. It examines how BC supports waste valorization, improves litter quality, enhances nutrient retention, lowers ammonia emissions, suppresses pathogen pressure, and reduces reliance on antibiotics, while also considering economic feasibility and regulatory conditions for wider adoption. Current evidence shows that BC has promise as a multifunctional intervention that links technological performance with environmental management and resource circularity in poultry production. At the same time, reported outcomes remain uneven because BC properties vary with feedstock origin and pyrolysis conditions, and because validation under commercial production settings remains limited. The review argues that the contribution of BC to sustainable poultry systems depends not only on biological and physicochemical performance, but also on standardization, cost effectiveness, policy support, and integration within circular agricultural value chains. Its functions align with key Sustainable Development Goals, particularly SDG 2 through more sustainable food production, SDG 6 through improved water quality and reduced nutrient losses, SDG 12 through waste valorization and responsible resource use, and SDG 13 through emission mitigation and carbon retention. BC therefore holds strong potential to support more resource-efficient and lower-emission poultry production, although broader implementation requires clearer production standards, stronger scale-relevant evidence, and more coherent regulatory guidance.