Poultry Litter Types and Co-Products
Poultry Litter Types and Co-Products
July 2025 | Written by: Sapana Pokhrel, Amy Shober, and Georgie Cartanza
Introduction
The Delmarva region is a significant center for poultry production, with over 600 million chickens raised in 2024 (Delmarva Chicken Association, 2025). Regionally, the poultry industry generates a substantial amount of poultry litter–a valuable organic resource. We estimate that nearly 700,000 tons of poultry litter are produced in the Delmarva region annually. This factsheet focuses on broiler litter, which is composed of bedding materials and manure, rather than layer manure which has little to no bedding and is high moisture content.
Poultry litter serves as a nutrient-rich organic fertilizer, providing the essential nutrients required for optimal plant growth. The exact nutrient content of poultry litter can vary widely depending on several factors, including:
● Type of bedding material used (e.g., pine shavings and miscanthus grass commonly used in the Delmarva region)
● Age of the litter
● Litter management practices within the poultry house or during storage
● Type of litter, such as:
○ Crust-out litter
○ Partial house clean-out
○ Whole-house clean-out
○ Composted mortalities
Nutrient variability can be minimized by analyzing poultry litter prior to land application.
While beneficial, poultry litter can present considerable management challenges. For example, transportation and application of the bulky material can pose logistical hurdles. Additionally, some agricultural fields on Delmarva already have elevated levels of phosphorus (P), an essential plant nutrient found in poultry litter. Careful management is necessary to avoid excessive accumulation of P in soils because P losses from agricultural fields can result in water quality concerns.
Fortunately, innovative solutions in the form of co-products, such as poultry litter ash and biochar, offer promising ways to address litter management challenges. The conversion of poultry litter into ash or biochar provides several advantages (Sharpley et al., 2007) including the reduction in odor, a significant decrease in overall volume, and an increase in the concentration of key nutrients like P and potassium (K). Furthermore, these poultry litter co-products can enhance nutrient release to crops and help reduce nutrient loss into water bodies, thereby supporting both agricultural productivity and environmental stewardship. However, N is usually lost during the conversion of litter to litter co-products.
In this fact sheet, we will discuss the various types of poultry litter and litter co-products with a focus on their properties, their potential benefits for crop farmers, and important management considerations. By understanding how these materials are generated, how to estimate their nutrient content, and how to address potential management challenges, farmers can better integrate litter or litter co-products into their nutrient management plans for sustainable crop production and reduced environmental impact.
Poultry Litter Types
Poultry litter is a mix of bedding material, chicken manure, feathers, and spilled feed that accumulates in chicken houses. Different litter conditioning techniques result in different litter consistency.
Poultry Crust
Poultry crust, also called "litter crust" or "cake," is the top layer of bedding found in broiler chicken houses closest to the foundation and drinker lines. This material is a blend of bedding, fresh manure,and water that is typically 1 to 3 inches thick. Crust may be removed after each flock of chickens or may be composted in the house (e.g., windrow composting).
Things to Consider:
Ease of handling from house to store than to the field but difficult to spread : The crust is chunky that makes it easier to handle and load compared to very loose or wet litter but difficult to spread in the field
Source of nutrients: Crust is high in important nutrients like nitrogen (N) and P. Research in Mississippi showed that the total N content varied from about 70–87 pounds per ton and total P ranged from 34–40 pounds per ton; nutrient content varied seasonally (Sistani et al., 2003).
High moisture content: Broiler cake typically has a moisture content of 40–60% (Macklin et al., 2008), which can cause litter to clump, making it more difficult to spread evenly in the field.
Reduced volume: Less litter is removed when crusting out compared to a full house cleanout, meaning that smaller quantities are available for use by crop growers at any given time.
Partial Cleanout
A "partial cleanout" involves removing a limited amount of litter, usually from the middle of a poultry house, after a year or production is when you cut the center out 5-6 flocks. This process is more about reducing litter depth while also retaining litter so you do not have to bring in additional bedding.
Things to Consider:
Supply consistency: Partial cleanouts are performed more frequently than whole-house cleanouts, potentially offering a more consistent, though smaller, supply of litter.
Higher moisture content: The litter removed during a partial cleanout typically often has moisture content exceeding 30% because poultry producers may target wet areas of the poultry house to remove litter from when cutting down the litter depth. Smaller volume: The total amount of litter removed from the house is less than for a whole-house cleanout, resulting in smaller quantities available for use on crop land at any given time.
Total or Whole House Cleanout
A "total" or "whole house cleanout" is when all the poultry litter is removed from a chicken house. This happens less often than partial cleanouts or broiler cake removals. In a 2020 survey, Delmarva poultry producers reported doing a whole-house cleanout, on average, once every three-five years.
Things to Consider:
Larger volume: The whole house cleanout process involves the complete removal of all bedding material, feathers, and other debris, resulting in a substantial volume of litter for land applications to crop land.
High nutrient and organic matter content: Litter obtained during a whole house cleanout often contains higher nutrient levels per ton compared to litter from cake removal or a partial cleanout. Higher nutrient content is typically related to a longer residence time in the house with nutrients accumulated over many flocks. Based on litter analysis from some poultry farms in Delaware, we found that older litter (resulting from a whole house cleanout following more than six flocks of birds) could contain about 50–60 pounds of total N per ton, 45–55 pounds of total P (as P2O5) per ton, and 55–75 pounds of K (as K2O) per ton. Older litter tends to have higher P content due to repeated inputs and limited mobility, while inorganic N content may vary or even decline over time due to ammonia volatilization (Feng et al., 2023). In contrast, newer litter (removed from a house that has had six or fewer flocks of chickens since the last whole house cleanout) may retain higher initial N concentration and lower P (P2O5) compared to older litter. Regardless of age, whole-house litter is rich in organic matter from bedding, feathers, and manure, which improves soil structure and microbial activity when land-applied.
Unpredictable availability: Total cleanouts happen less often, making it a less consistent source of litter for crop production.
Logistics and Management challenges: The sheer volume of broiler litter presents significant logistical challenges that make a total house clean-out a less frequent practice for growers. The timing of a full clean-out is driven by several key factors, including the depth of the litter, the disease pressure within the house, the time available between flocks, and the availability of new litter material. Ultimately, the relationship and coordination between the poultry grower, the receiving farmer (for nutrient application), and the availability of specialized equipment often dictate when a full clean-out can be performed. This makes litter management a complex, continuous process rather than a simple, one-time task.
Mortality Compost
Mortality compost is made by composting dead chickens with poultry litter or another carbon source. When done correctly, this composting process transforms the carcasses into a valuable product for soil enrichment. Proper composting is an aerobic process, meaning it happens in the presence of oxygen, and it effectively breaks down carcasses and bones, prevents the spread of diseases, and protects air and water quality. However, if composting is not managed correctly, it can lead to problems. An improper process can result in the incomplete breakdown of carcasses, causing unwanted odors and attracting flies. It can also lead to the uneven distribution of nutrients throughout the final compost, reducing its value as a soil amendment.
Things to Consider:
Nutrient rich: Mortality compost generally contains higher concentrations of nutrients than other litter types. The actual nutrient content of mortality compost is variable and depends on the nutrient content of the dead chickens themselves, as well as the carbon source (e.g., poultry litter or straw) used in the composting process.
Nutrient stability: The composting process stabilizes organic matter, making nutrients in the compost available to plants over a longer period compared to other litter types.
Pathogen and odor reduction: Proper composting generates high temperatures that reduce most pathogens, making the end product more uniform and reducing odor and ready to apply to land.
Variable quality: It is very important for crop farmers to ensure that any mortality compost they receive was properly composted. If composting is not done correctly, it can lead to the spread of disease-causing organisms, the incomplete breakdown of carcasses, and an uneven distribution of nutrients throughout the compost.
Poultry Litter Co-products
Poultry litter co-products are specially processed forms of poultry litter. Poultry litter co-products are more stable, release nutrients slowly, and take up less space compared to raw poultry litter, making them appealing to farmers.
Poultry Litter Ash
Poultry litter ash is a material created from poultry litter that can be used as a source of plant nutrients and even as a source of "green energy." To make poultry litter ash, raw poultry litter is burned at very high temperatures (over 1830℉) in presence of oxygen. Poultry litter ash can also be treated with phosphoric acid.
Things to Consider:
Significant volume reduction: The ashing process significantly reduces the volume of the original litter.
Concentration of nutrients: Nutrients in the ash become much more concentrated, sometimes up to ten times higher than in raw litter, making ash a more potent fertilizer.
Ease of transport: Because the volume of litter ash is smaller than for raw litter, poultry litter ash is easier and cheaper to transport.
Liming agent: Poultry litter ash can act as a liming agent, helping to reduce soil acidity.
Soil benefits: Poultry litter ash is a useful material for improving soil, stimulating microbial activity, and improving the soil's ability to hold water.
Loss of organic matter and N: The high heat involved in burning destroys the organic matter and a lot of the N that was present in the original litter.
Reduced P solubility: The P in the ash may become less available to plants because it is converted to a chemical form that does not dissolve as easily in water.
Fine dust particles: The ash can produce very fine dust particles during handling.
Nutrient composition variability: The nutrient composition varies and is dependent on the original litter source, bedding type, feeding type, bird age, and the specific combustion system used. The amount of P in poultry litter ash is similar to that found in common commercial fertilizers, like triple superphosphate and potassium phosphate (Codling, 2002; Crozier, 2009). As such, poultry litter ash may be a poor option for fields with “excessive” soil test P concentrations (i.e., Mehlich-3 P greater than 100 mg/kg or UD-FIV).
Poultry Litter Biochar
Poultry litter biochar is produced through processes called pyrolysis or gasification. These methods involve heating the poultry litter to high temperatures (around 750−900℉) in an environment with very little to no oxygen.
Things to Consider:
Volume reduction: Poultry litter biochar provides a sustainable way to significantly reduce the volume of poultry litter, sometimes by up to 60%, making it much easier to transport.
Nutrient enrichment: The pyrolysis and gasification processes concentrate nutrients, resulting in biochar with high nutrient content compared to the original litter. Litter biochar adds important nutrients like calcium (Ca), magnesium (Mg), and K to the soil, making them more available for plants to absorb compared to raw poultry litter (DeLuca & Gao, 2019; Masud et al., 2020).
Nutrient retention: The resulting biochar has a higher cation exchange capacity (CEC) compared to biochar made from other plant materials (Gaskin et al. 2008). Materials with higher CEC are able better to hold onto essential nutrients.
Liming agent: Poultry litter biochar can act as a liming agent, helping to reduce soil acidity.
Improved soil conditions: Adding litter biochar to the soil can improve the soil's ability to hold water, which is especially helpful during dry periods. In addition, adding biochar to soils can reduce the soil's bulk density, meaning the soil becomes less compacted, making it easier for roots to grow and water to infiltrate.
Reduced P runoff risk: Biochar can help reduce the amount of P that dissolves in water (Cao & Harris, 2021; Wang et al., 2015). This is important because it lowers the risk of P running off fields and into water bodies like the Chesapeake Bay.
Strict processing requires: The generation of biochar requires specialized processes (i.e., pyrolysis or gasification), which may not be available in all locations.
Loss of N: Poultry litter biochar is also known for its high ash and carbon content when compared to biochar made from materials like pine (Das et al., 2008). However, the high temperatures used in pyrolysis or gasification results in the loss of N and, therefore, lower N concentrations than raw litter.
Cost: Litter biochar is expensive. Plus this material should be incorporated into soils after application, requiring tillage operations and limiting its use in no-till systems.
Importance of Nutrient Testing
As highlighted throughout this fact sheet, the nutrient content of poultry litter and its co-products can vary significantly based on many factors. To ensure you are applying the correct amount of nutrients to your fields and to avoid over-application, it is critically important to have your litter analyzed. Knowing the exact nutrient profile of your poultry litter or co-product will allow you to optimize application rates to match crop nutrient requirements, which could save money by reducing the need for additional inputs and also prevent nutrient losses from the land that could negatively impact water quality.
For farmers in Delaware, analysis of manure (including litter and litter co-products) is available for free at the Delaware Department of Agriculture’s Agricultural Compliance Laboratory. Taking advantage of this analytical testing service before applying litter or litter co-products to your fields is a key step toward sustainable nutrient management. For more information about how to collect a poultry litter sample and have it analyzed for nutrient content, please refer to Know the Value of Manure Manure Sampling and Analysis (available at http://www.udel.edu/0013476; Riggi & Shober, 2025).
Summary
Farmers have a variety of options for managing nutrients and enriching their soil using different types of poultry litter and litter co-products. Each of these materials offers unique properties and benefits, ranging from nutrient-rich organic fertilizers to stable soil amendments.
However, successful utilization of poultry litter and litter co-products requires careful consideration and planning. Farmers must be mindful of factors such as nutrient content variability, potential for nutrient loading into the soil, availability, and cost. By conducting nutrient analysis of poultry litter prior to application and implementing appropriate management practices, farmers can optimize nutrient use while minimizing environmental impacts.
References
Codling, E. E., Chaney, R. L., & Sherwell, J. (2002). Poultry Litter Ash as a Potential Phosphorus Source for Agricultural Crops. Journal of Environmental Quality, 31(3), 954-961. https://doi.org/10.2134/jeq2002.9540
Crozier, C. R., Havlin, J. L., Hoyt, G. D., Rideout, J. W., & McDaniel, R. (2009). Three Experimental Systems to Evaluate Phosphorus Supply from Enhanced Granulated Manure Ash. Agronomy Journal, 101(4), 880-888. https://doi.org/10.2134/agronj2008.0187x
Das, K. C., Garcia-perez, M., Bibens, B., & Melear, N. (2008). Slow pyrolysis of poultry litter and pine woody biomass: Impact of chars and bio-oils on microbial growth. Journal of Environmental Science and Health, Part A, 43(7), 714–724. https://doi.org/10.1080/10934520801959864
Delmarva Chicken Association. (2025). DCA Facts & Figures. https://www.dcachicken.com/facts/facts-figures.cfm
DeLuca, T. H., & Gao, S. (2019). Use of Biochar in Organic Farming. In C. Sarath Chandran, S. Thomas, & M. Unni (Eds.), Organic Farming (pp. 41–60). Springer. https://doi.org/10.1007/978-3-030-04657-6_3
Feng, H., Prasad, R., & Chakraborty, D. (2023). Effects of broiler litter age and application rate on nutrient mineralization under laboratory conditions. Agrosystems, Geosciences & Environment, 6(4), e20445. https://doi.org/10.1002/agg2.20445
Gaskin, J. W., Steiner, C., Harris, K., Das, K. C., & Bibens, B. (2008). Effect of low-temperature pyrolysis conditions on biochar for agricultural use. Transactions of the ASABE, 51(6), 2061-2069. https://doi.org/10.13031/2013.25409
Macklin, K., Campbell, J., Simpson, G., & Donald, J. (2008). Managing built-up litter in broiler houses. Alabama Cooperative Extension System. https://ssl.acesag.auburn.edu/dept/poultryventilation/documents/Nwsltr-56ManagingBuilt-UpLitter.pdf
Masud, M. M., Abdulaha-Al Baquy, M., Akhter, S., Sen, R., Barman, A., & Khatun, M. R. (2020). Liming effects of poultry litter derived biochar on soil acidity amelioration and maize growth. Ecotoxicology and Environmental Safety, 202, 110865. https://doi.org/10.1016/j.ecoenv.2020.110865
Riggi, S. Y., & Shober, A. L. (2025). Know the value of manure: Manure sampling and analysis. University of Delaware Cooperative Extension. http://www.udel.edu/0013476
Sharpley, A. N., Herron, S., & Daniel, T. (2007). Overcoming the challenges of phosphorus-based management in poultry farming. Journal of Soil and Water Conservation, 62(6), 375-389. https://doi.org/10.1080/00224561.2007.12436007
Sistani, K. R., Brink, G. E., McGowen, S. L., Rowe, D. E., & Oldham, J. L. (2003). Characterization of broiler cake and broiler litter, the by-products of two management practices. Bioresource Technology, 90(1), 27-32. https://doi.org/10.1016/S0960-8524(03)00096-8
Wang, Y., Chiu, Y. P. T., Imhoff, M., & Guo, M. (2015). Phosphorus release behaviors of poultry litter biochar as a soil amendment. Science of the Total Environment, 512, 454-463. https://doi.org/10.1016/j.scitotenv.2015.01.093
About the Authors
Sapana Pokhrel, Postdoctoral Researcher, University of Delaware, Newark, DE
Amy L. Shober (corresponding author), Professor and Extension Specialist, University of Delaware, Newark, DE
Georgie Cartanza, Poultry Extension Agent, University of Delaware, Georgetown, DE
About the Publication
Original publication date: 2025
Peer Reviewers
Drew Harris, Extension Agent, University of Delaware Cooperative Extension, Dover, DE
Sydney Riggi, Extension Agent, University of Delaware Cooperative Extension, Dover, DE
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