Chicken manure is one of the most nutrient-rich livestock and poultry manures—dry chicken manure can contain up to 50% organic matter, 3.2% nitrogen, 3.1% phosphorus (P₂O₅), and 2.4% potassium (K₂O). However, uncomposted chicken manure contains a large number of pathogens, insect eggs, and parasites, and direct application to the soil can cause root and seedling burn. Therefore, chicken manure must undergo a complete fermentation process of deodorization, sterilization, and dehydration before it can be safely returned to the field.

Pretreatment: Adjusting the Carbon-Nitrogen Ratio and Moisture Content

Fresh chicken manure has a high moisture content (up to 80%) and a low carbon-nitrogen ratio, making direct fermentation difficult to achieve. The core task of pretreatment is to adjust the moisture content to 55%-60% and the carbon-nitrogen ratio to 20-35:1.

Specific Operation: Add auxiliary materials such as straw, rice husks, sawdust, and peanut shells with a carbon-nitrogen ratio of 20-80:1 at a ratio of 3:1 (chicken manure to auxiliary materials). Simultaneously, add 1-2 kg of fermentation bacteria per ton of material, controlling the particle size to below 5 cm and the pH value between 5.5 and 9. Ideal moisture content is achieved when the material can be formed into a ball by hand but crumbles easily upon release.

Deodorization is initiated simultaneously at this stage. Compound lactic acid bacteria perform anaerobic fermentation for deodorization, while thermophilic Bacillus, yeast, and actinomycetes effectively inhibit the release of ammonia and hydrogen sulfide. Additives such as biochar can reduce the emission of sulfur-containing odorous components by up to 65.3%.

Fermentation: High-Temperature Sterilization and Aerobic Turning

Chicken manure fermentation utilizes an aerobic high-temperature composting process—rapid heating, high temperature, and short composting cycle, effectively killing insect eggs, pathogens, and weed seeds.

Pile the pre-treated material into a fermentation tank (tank process) or into windrows 70-80 cm high and 1.5 meters wide. Cover the surface of the pile with approximately 30 cm of well-rotted manure for insulation.

Temperature is the core indicator for sterilization. After 2-3 days, the pile temperature can reach 60℃, at which point the first turning should be performed. After another 3-4 days, the pile temperature rises above 70℃, and it should be turned again. The pile temperature should be maintained above 55℃ for at least 7 days – this is crucial to ensure thorough sterilization. When the pile temperature exceeds 65℃, it needs to be turned promptly to cool it down and prevent overheating from killing beneficial bacteria. The turning frequency is generally 1-2 times per day. With turning and high temperature, the moisture content of the chicken manure gradually decreases to below 30%.

The trough-type aerobic fermentation cycle is usually 15-20 days, with the core temperature of the pile gradually decreasing, completing the first fermentation. If further maturation is required, the material can be transferred to an aging chamber for a second fermentation of 15-20 days, turning it every 2-3 days until the pile temperature approaches ambient temperature and there is no odor or fly larvae.

III. Maturity Standard: Seed Germination Index (GI) Whether fermentation is complete cannot be judged by sensory perception; it must be scientifically evaluated using the seed germination index (GI). GI (Gross Accumulation Index) is a biological indicator that comprehensively evaluates the maturity of compost: GI > 50% indicates basic maturity, and GI ≥ 80% indicates complete maturity. The Ministry of Agriculture and Rural Affairs industry standard NY/T525-2021 stipulates that the GI value of organic fertilizer should be ≥ 70%.

It is worth noting that chicken manure is more difficult to compost than other manure sources—the GI value of fermented chicken manure is often much lower than that of cow or sheep manure. Production enterprises need to strictly control the fermentation process, extending the fermentation cycle or adjusting the microbial strain if necessary, to ensure that the product meets the standard requirements.

The complete chicken manure fermentation process – from moisture and C/N adjustment, high‑temperature aerobic turning, to maturation and GI testing – is the indispensable foundation for producing safe, high‑quality organic fertilizer. Each step is enabled by specialized organic fertilizer machine systems, starting with an animal manure processing machine and chicken manure fertilizer machine for dewatering and preconditioning, followed by the critical chicken manure fermentation turning process that ensures uniform aeration, temperature control, and pathogen elimination. This well‑orchestrated organic fertilizer production process transforms raw manure into a stable, odorless, and nutrient‑rich product, ready for further processing in a commercial organic fertilizer production line – including crushing, granulation, drying, and packaging. For dedicated poultry operations, a poultry manure fertilizer making machine can be integrated to handle high‑moisture feedstock efficiently, while trough or windrow turners maintain the aerobic conditions essential for rapid decomposition. By strictly controlling fermentation parameters – maintaining pile temperature above 55°C for at least 7 days, achieving a seed germination index ≥70%, and reducing moisture to below 30% – producers can consistently convert a potential environmental hazard into a valuable soil amendment. Ultimately, mastering this complete process not only ensures compliance with organic standards but also unlocks the full agronomic potential of chicken manure, delivering a premium product that improves soil health and boosts crop yields – a true win‑win for farms, the environment, and the fertilizer industry.

In summary, the complete path of chicken manure fermentation is: pretreatment with water and carbon content adjustment → high-temperature aerobic fermentation sterilization and deodorization → aging and secondary maturity → GI testing and certification. Mastering this process allows chicken manure to be transformed from a pollution source into a valuable organic fertilizer resource.