Linear poultry waste disposal severely threatens the environment and public health. This critical review aims to examine circular bio-economy strategies for transforming manure, litter, feathers, offal, and hatchery waste by organizing pathways by waste stream and evaluating each against technical maturity, economic viability, environmental risk, and regulatory readiness. Its novelty lies in integrating stream-specific valorization with multi-criteria evaluation, replacing superiority claims with evidence-graded assessment, and proposing a numerically scored three-tier rubric with confidence ratings. A targeted search of Scopus, Web of Science, Google Scholar, and PubMed identified peer-reviewed and grey literature (1992–2026). From 389 full-text articles, 85 core documents formed the evidence base. Data were extracted for comparative multi-criteria evaluation. This is a critical review, not a systematic review; no pooled statistics are reported. No single technology fits all streams. Mono-digestion of poultry litter yields 0.10–0.20 m3 CH? kg?1 volatile solids (VS), while co-digestion increases yields to 0.31–0.34 m3 CH? kg?1 VS. Composting achieves ≥2log pathogen reduction, and rendering inactivates pathogens at 133 °C, 3 bar, 20 min. Economic thresholds for composting (>?3,000 hens) and biogas (>?10,000 birds) derive from one conference paper and are low-confidence. Composting and rendering are mature Tier 1 pathways; direct land application is complementary. Anaerobic digestion yields renewable energy but requires co-substrates, thermochemical routes handle mixed wastes; green extraction recovers biomolecules with unproven scalability. Critical gaps include scarce life-cycle assessments, un-scaled feather bioconversion pathways, and localized biosecurity regulatory fragmentation. The three-tier hierarchy provides a transparent decision-support tool for policy, industry, and research.