Compost Systems & Technologies

Systems to feed laying hens food scraps in commercial operations are still evolving. Generally, a farm’s set-up reflects the scale of the operation and the role of food scraps in the feed ration.

Feeding

Some operators feed their hens exclusively on food scraps, compost, and pasture with mineral supplements, while others offset a portion (5-50%) of their purchased feed with food scraps.  In Vermont, when this practice is occurring with flocks over 40 birds, the food scraps are typically imported from surrounding communities.

Experience from two laying operations where food scraps and compost are 100% of the feed ration suggests that providing 2 pounds of food scraps per day works well.  It appears hens will eat up to 1.5 pounds of food scraps daily, however not all of the food scraps provided will be desirable or edible to the hens.  Therefore, modestly over-budgeting the food scrap amounts is advisable and supports the hens’ ability to fill themselves while using discretion about what they choose to eat.

Sourcing Food Scraps

Typically food scraps are captured from grocers, restaurants, schools and colleges, hospitals, residents (through drop off programs at recycling centers), prisons, corporate and state cafeterias, resorts, food processors, brewers, distillers, and other food-based businesses and institutions.  Collection systems range in scale and mechanization.  Some farms do not haul food scraps and receive loads from commercial or municipal haulers, while others self-collect using methods including small containers (5-32-gal) in the back of a pick up truck, medium size containers (32-48 gal) on a flatbed trailer, or larger containers (48-64 gal) with mechanical systems for tipping containers into a dump trailer or truck.  Where small and medium sized containers are collected and food scraps are transported in the container, operators exchange clean containers (requiring extra containers) for full ones, while operators tipping containers into a truck or trailer carry onboard washing systems and clean containers on-site once they have been tipped.  These systems carry their own water and collect wash water in with the food scraps.

Handling and Feeding Food Scraps

Handling and feeding food scraps requires good infrastructure and husbandry.  Like other aspects of one’s farm operation, the handling and feeding food scraps system must work reliably and every day.  Therefore the parts of the system need to function under all potential circumstances.  For example, predictable access to the tipping location throughout the year is critical.  Useful features of food scrap feeding infrastructure include:

• Access Road(s) – Stable road surfaces and plenty of turning radius.

• Tipping Dock – In most cases the operator will benefit from having an elevated platform for tipping loads into a receiving or feeding bin.

• Feeding System – This is an organized, contained, and manageable system to feed materials with adequate access for tipping loads, blending materials, and removing contents. These systems can be mobile or static and can be designed to support feeding food scraps alone or in a compost blend. A Feeding Bin can be useful in giving hens contained access while providing equipment with a place to blend materials and push walls for easy removal. Covering the feeding area will increase hen foraging in inclement weather, keep mix drier, and prevent snow from accumulating on the food scraps.

• Compost Management System – Under most scenarios there will be residual food scraps that the hens don’t eat. If the food scraps have not already been blended with a carbon material to support composting, the residuals will need to be combined with dry matter and carbon. Either way this system will result in a combination of uneaten food and other organic materials requiring management. The operator will need a place sufficiently large and easily accessible to actively manage this composting process. This can be within or outside of the feeding system.

The primary and obvious difference in handling food scraps as opposed to grain is the moisture content and putridity of the food scraps.  As a result of this high moisture, ‘ready-to-rot’ condition, food scraps have the potential to cause odors, create environmental pollutants, attract rodents, skunks and other unwanted critters, and potentially, create poor animal health conditions.  Additionally, moisture content makes food scraps prone to freezing in cold temperatures, making the food unavailable to hens for eating.

By integrating the feeding of food scraps into a composting strategy the operator can mitigate these concerns, while also gaining other benefits.  The composting process requires blending the food scraps with other organic materials, of which a good portion must be dry carbon material to support active composting.  This requires that the operator secure these other materials proportionately to the amount of food scraps they anticipate handling.  When these materials are blended they create the conditions to support exponential growth in the beneficial microbial population, especially bacteria.  This process mitigates odor creation, leachate, colonization by pathogenic organisms, and produces heat that keeps the materials from freezing. In some cases the feeding pile remains free of snow.  Additionally, there is reason to believe that by culturing microbes in the food scraps we can increase the protein available to the hens and gain other health benefits associated with grazing birds.  In order to support these conditions, the handling system must lend itself to passive pile aeration, blending and rolling, and operator management.

Economic Benefits

As noted earlier, one of the clearest benefits of feeding food scraps to laying hens is reduced feed cost.  The range of savings on feed depends on whether the grain is bulk or retail, conventional or organic.  Another economic benefit is potential new revenue from tipping fees (a fee paid to the farmer by the hauler who delivers the food scraps).  In scenarios where producers receive a tipping fee for accepting food scraps, the operator is able to turn feed from a large cost to a modest income.  In addition, like pastured or organic eggs, there may be a marketing opportunity for eggs produced by a method that uses of a locally available resource – food scraps – instead of imported feed. Additionally, if current and future research reveals nutritional attributes of the eggs similar to pasture raised layers, the health benefits will become a strength in creating additional value.

Labor

The trade off from reduced feed costs with this system is higher and different labor costs. Adequate scale and facility development can reduce labor demands significantly, though initial capital costs will increase.  Mechanizing the tote handling and washing system provides dramatic reductions in labor costs per ton of food scraps handled.  Covered feeding areas with adequate space for managing several weeks of food scraps in one place will reduce snow management and materials movement (food scraps, and especially food scraps blended into a compost mix will reduce in volume over time).

Pathogens

While farmers have been feeding food scraps to laying hens for hundreds, if not thousands, of years, the resurgence of this practice for commercial flocks has raised issues about potential pathogen pathways. Current research (scheduled for release in late 2015) has narrowed down that concern, with Salmonella Entridis the pathogen of most concern.  The concern is that s. Entridis could be brought into the laying operation and hen exposure in feed could result in the vertical transmission into eggs.  From the testing already conducted on three farms (including one not following best practices) researchers have not identified elevated levels of pathogens.

To mitigate pathogen concerns, feeding food scraps in a composting system enables the producer to grow out a dynamic bacterial and fungal food web that will prevent bacteria of concern from reaching pathogenic levels (due to resource competition for the most part). While questions remain about how to best manage this integration and optimize pathogen management, adequate literature exists to substantiate the efficacy of composting systems in destroying and managing pathogen colonies.  Since hens are benefiting from this microbial diversity and abundance year round, there may in turn be animal health benefits we do not yet fully understand.

Advancing the Practice

A Northeast Sustainable Agriculture, Research and Education (NE SARE) grant supported a collaborative research project between Black Dirt Farm (Stannard, VT), Cornell University, University of Connecticut and two participating farms in central and northern Vermont to further assess aspects of this practice as discussed here. (Results available after January 2016)  Further research and documentation is needed to advance this practice, and fully leverage the opportunity presented by State legislation banning discarded food from the landfill.

Text provided by Tom Gilbert, Black Dirt Farm, Stannard, VT, USDA/SARE grant recipient, 2014

Additional Links and Resources

• Layer Flock Budget Worksheet (from Intervale) (.XLS format)

• Compost Recipe Development Worksheet

• Farm to Plate Strategic Plan Analysis of Vermont Egg Market

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This resource is content originally developed by the Highfields Center for Composting in Hardwick VT. The Highfields Center for Composting dissolved as an organization in December 2014 and ended its active involvement in the Close the Loop Program. The content has been made publicly available for use in supporting organics management in Vermont and elsewhere through the generosity of the High Meadows Fund, the Harris and Frances Block Foundation, and the Vermont Community Foundation. The Vermont community wishes to thank the Highfields Center for Composting for its years of outstanding leadership in the service of community composting and universal recycling in Vermont.

On Thursday, October 26th, members of the Vermont Ecological Sanitation Coalition joined CAV for a conversation about the environmental and societal benefits of ecological sanitation for Vermont, the safety of humanure composting, and current regulatory options.

We addressed misconceptions about compost toilet systems, shared some best practices, and discussed the possibility of CAV developing training for successfully using these systems.

Video time stamps:

• 0:00 Introduction to the session and guests

• 3:23 What is the Vermont Ecological Sanitation Coalition & why does it exist

• 6:45 What are compost toilet systems

• 17:59 Discussion about misconceptions, research, and testing

• 37:18 General discussion

Shared resources

• Point of Shift

• Nutrient Networks

• A summary of the regulatory landscape & a link to last year’s bills is under “Compost Toilets” on Rich Earth Institute’s website.

Please fill out this survey to let us know your thoughts so that we can gauge interest in this topic.

Jim Stiles has been experimenting with producing Johnson-Su compost at his home in St. Albans for about ten years. His initial reactors were not up to the challenges posed by Vermont’s winter - they froze, effectively ending early experiments. In response, he switched gears and created his first micro-reactor (in a sleeved 5-gallon bucket) and then six more, slightly larger reactors (in 20-gallon fabric pots), which he moved into his basement for the winter to avoid the freezing problem.

This approach mostly worked but also suffered from some shortcomings. A new generation of 5-gallon micro-reactors are currently working in his basement. The results so far include superior management of leachate (creating a valuable by-product to boot) and faster processing of feedstock.

This is a video of the VORS 2024 hands-on workshop that involved emptying and examining the contents of a reactor to assess its progress. Participants were encouraged to participate in this examination and share observations.

This VORS 2021 webinar discusses traditional thermophilic composting and vermicomposting, two very different systems promoting different microbial communities. Mature thermophilic compost is generally slow to release nutrients and is inexpensive. In contrast vermicompost already has high levels of available nutrients and is about 10 times the price of thermophilic compost. The research presented explores potential synergistic nutrient release effects when the two compost types are mixed.

Speaker and Video time stamps:

• Josef Görres, starts at 5:56

• Q&A, starts at 50:45

This virtual tour of Rich Earth Institute was part of VORS 2021. Rich Earth Institute engages in research, education and technological innovation to advance the use of human waste as a resource. Rich Earth operates the nation’s first community scale urine recycling program, reclaiming the nutrients from our bodies as a sustainable fertilizer for local farms, reducing downstream nutrient pollution, and conserving clean potable water. This program serves as a platform for controlled agricultural field trials with urine fertilizer, as well as both lab and social research.

In this virtual tour, learn about how their community-scale program operates and the future of urine nutrient reclamation in the Southern Vermont region and beyond!

Video time stamps:

• The tour starts at 2:21

• Q&A with Arthur Davis starts at 19:21

In this VORS 2025 session, panelists explore methods for composting unconventional feedstocks and share innovative approaches to processing human urine, liquid waste, and other nutrient-rich materials. Learn how these practices reduce waste, enhance nutrient management, and support soil health. From small-scale demonstration projects to commercial applications, this session will offer actionable insights and inspire new ways to transform waste into valuable compost products. 

Facilitator: Dan Goossen, CSWD

Panelists and Video time stamps:

• 1:49-21:54 Benson Colella, Wasted PBC

The potential of urine as a sustainable nutrient input for compost

Urine is rich in nutrients like nitrogen, potassium, and phosphorus, yet these nutrients are often lost to the watershed through traditional wastewater treatment.  This presentation will explore how urine collected from specialized toilets can serve as a sustainable alternative to chemical fertilizers, thus reducing reliance on mining and fossil fuels.  We will discuss the nutrient composition of urine and its regulatory and processing requirements for use as a soil amendment.  We will share preliminary results from an experiment in which commercial-scale leaf litter compost was supplemented with urine.  Those findings will compare nutrient profiles of the urine-supplemented compost to a control and share operational insights into the urine supplementation of compost at-scale. 

• 21:54-51:11 John Culpepper, Compost for Good

Composting human urine. What? Why?

Compost for Good operates a modest facility, registered by the New York State Department of Environmental Conservation to process diverted human urine through a high temperature composting process. This Human Urine Research and Demonstration facility is open to entrepreneurs, policy makers, farmers, and others. To date we have successfully processed over 2,000 gallons of urine, producing numerous cubic yards of high quality, high value, biologically robust compost. We have also experimented with different recipes, mixing urine, food scraps, spent brewery grain, and other nitrogenous materials using densified wood pellets and wood chips as a carbon source.  In this presentation I will share our successes, and show examples of finished compost images of the various compost recipes under a microscope.

• 51:11-1:39:10 Jean Bonhotal, Cornell Waste Management Institute

Composting Eggs, Milk, Whey, Manure, Blood, and Other Difficult Liquids from Disaster

Composting liquids can be an important part of the composting process as moisture is essential for dry carbon resources.  Eggs in the billions, dairy residuals, blood, offal, liquid manure, high BOD liquids from flooding are a very difficult task, but it is doable.  We need more than one tool in the toolbox to properly dispose of liquids. Form a bowl or volcano to absorb the liquid before it’s able to hit the ground, creating these depressions in very thick carbon layers is the key. 15,000 gallons of milk waste can be placed into a 100 ft windrow weekly for 6 to 8 weeks. Mix it all together on site and load it into a loader/ truck/ bucket and form windows out of that mixture.  Composting liquids is a win/win option.