The use of antibiotic growth promoters (AGPs) in poultry production has raised concerns for human, animal, and environmental health owing to the development and spread of antimicrobial resistance. These concerns have triggered global efforts to decrease AGP use and have intensified calls for sustainable, antibiotic-free production. Antibiotic-free production aims to safeguard food security and safety while mitigating environmental risks; however, it faces challenges, including reduced productivity, increased disease susceptibility, and economic constraints. This systematic review assesses the current knowledge of AGPs and their alternatives in poultry production and identifies key research gaps. It examines the mechanisms through which AGPs promote growth and antimicrobial resistance, and the challenges and opportunities associated with antibiotic-free poultry systems, including regulatory and sustainability considerations. A total of 149 peer-reviewed articles published between 2005 and 2025 were identified following preferred reporting items for systematic reviews and meta-analyses guidelines. Evidence suggests that no single additive can consistently replace AGPs; rather, successful antibiotic-free production depends on integrated strategies targeting gut integrity, microbial ecology, and host immunity. Key inconsistencies in the literature include variable responses caused by diet composition, environmental conditions, and bird genetics, emphasising the need for mechanistic, systems-level approaches to optimise outcomes. Robust, scalable antibiotic-free systems will require coordinated advances in nutrition, management, and microbial modulation, supported by validation under commercial conditions. The transition from AGPs to sustainable, antibiotic-free poultry production requires coordinated action by researchers, policymakers, industry stakeholders, farmers, and consumers to establish resilient systems that deliver safe, high-quality products while promoting public health, food security, and environmental stewardship.

(Submitted 05 February 2026; Accepted 27 March 2026; Published 04 May 2026)