<p>This study investigates the physicochemical properties and potential uses of biochar made from the carbonization of chicken manure and various biomass feedstocks, including orange peel, pineapple peel, coconut husk, sawdust, and rice husk. Biochars were synthesized from chicken manure and various biomass feedstocks at different mixing ratios and characterized for yield, energy content, proximate and ultimate composition, surface morphology, and porosity. Results showed that chicken manure yielded the highest biochar at 47.88%, while 100% biomass-based samples, like pineapple peel and rice husk, exhibited superior properties, including high energy content (up to 28.23&#xa0;MJ/kg), surface area (up to 191.3 m²/g), and microporosity. Co-carbonization increased yield and nutrient content but decreased carbon content and porosity due to higher ash levels. Morphological analysis revealed agglomerated and porous textures in 50:50 blends, indicating multifunctional potential. The biochars demonstrated potential for various applications: high-energy biomass-derived biochars as solid fuels; porous biochars for adsorption in environmental cleanup; and nutrient-rich manure-based biochars for soil improvement. These findings support co-pyrolysis as a sustainable waste valorization method aligned with circular economy and bio-circular-green principles.</p> Graphical Abstract <p></p>