Effective use of food scraps as poultry feed

Final Report for FNE14-801

Project Type: Farmer
Funds awarded in 2014: $15,000.00
Projected End Date: 12/31/2017
Region: Northeast
State: Vermont
Project Leader:
Tom Gilbert
Winchester Farm
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Project Information


Black Dirt Farm and a small group of other farms in our region have raised laying hens on a diet of discarded food in an active composting systems for over ten years, however no quantitative assessment of this feeding strategy has been conducted, and we were interested to clarify any concerns with the transmission of salmonella. To this end, this project assessed the opportunities and risks associated with feeding food scraps to laying hens. Specifically, we looked at the nutritional value and pathogenic risks associated with food scraps as a feed, egg production and quality and the economic viability of this practice for small-scale commercial production (50-2500 hens).

This has been a three-year project. During the one-year trial we operated a split flock with 55 birds in each group. Group One was fed only a food scrap-based compost mix (Compost Group), while Group Two (Grain Group) was fed strictly Organic Grain. Both groups had year-round access to equal pasture and Fertrell’s Poultry Mineral Mix. Food scraps were thoroughly sampled with a rigorous sub-sampling process, and tested for nutrient composition and Salmonella enteritis.

  1. Eggs were tested for Salmonella enteritis and nutrient content, and coops were swabbed for Salmonella at our farm and a partnering farm using this practice and none was found.
  2. Egg production: grain hens had 2% more eggs than compost-fed hens however at various points the Compost Group was out-producing the Grain Group by as much as 10%.  Eggs from the Grain Group were 4% heavier on average. 
  3. Egg quality: Egg nutrition was similar in the Grain and Compost Groups with some surprising differences. Yoke color was much darker from the compost hens.
  4. Feed costs: It is projected that a 50-75% reduction in feed costs for a flock of 2,000 birds amounts to $30-42,000/ year, and new revenue associated with compost sales.
  5. Labor: The Compost Group required nearly twice the labor of the Grain Group, however the feed cost in the Grain Group represented over 85% of egg sales. 

Our trial demonstrated the viability of this practice and indicated opportunities for optimizing the system. Overall, while there were some differences, the outcomes were largely similar.  In addition to eggs, the Compost Group generated compost, of value both on the farm and in sales, and integrated with a profitable collection service. In terms of farm viability, the Compost Group was not only more profitable, it is also can be scaled more effectively. To a large extent as flock sizes increase, the feed costs follow the same trend. However, we are now managing 300 birds on the same system with the same amount of labor as we were with 50 hens, thereby spreading the same cost over six times more birds.

Based on the work in this project and other observation, we have produced Feeding-Community-Food-Scraps-to-Laying-Hens-in-an-Active-Composting-System-manual, an operator’s manual for considering and planning a compost-based feeding system.

Dr. Michael Darre, UCONN Poultry Specialist, worked with us on trial design and feed ration development. Dr. Jarra Jagne, Cornell University Poultry Pathologist, helped us assess the pathogen risk.


As long as humans have domesticated chickens and their predecessors, chickens have likely been consuming their discards in some capacity. In fact, fowl scavenging food in human communities may have contributed to domestication, leading to a longtime co-evolution. The practice continued and became more deliberate through the 1930s when a resource-mindful World War II-era US Government encouraged citizens to set aside food scraps from their trash for the purpose of feeding hens and pigs. In fact, the separation and collection of these materials was organized and government propaganda encouraged people to ‘Save Kitchen Scraps for the Hens! Your local council will collect’. Since that time there have been documented cases of pathogen transmission from humans to food scraps to pigs, which have brought about health concerns associated with feeding pigs food scraps. More recently we have come to understand the pathogen pathways between pigs and humans, however there has never been any documentation of this same risk with chickens. Many states regulate feeding discarded food to pigs, some banning it out- right. Some states have implemented similar measures for poultry, without precedent or scientific basis. As growers and communities throughout the world are looking for new models of agriculture and community resource management utilizing discarded food as poultry feeds is a practice attracting more interest in recent years. Further exploration of the practice will help ensure efficacy, safety and producer viability. This project has sought to contribute to that process for our own farm as we scale up our laying operation, and that of other growers.

Red Jungle Fowl are believed to be the species from which the modern chicken has descended. These jungle birds forage from the forest floor searching out bugs, fallen fruit, plant matter and seeds. Much of their diet is derived from the decomposer system. Biomimicry is the practice of attempting to replicate certain relationships and functions present in ecosystems in a constructed environment. In agriculture a wide variety of techniques have been developed and are under development to mitigate the impacts of disturbance by adopting systems that attempt to reflect native, or more ecological, systems.

The compost-based feeding system is an attempt to realize the nutritional value from food scraps, the fallen fruit of the food system, while also mimicking the biological system of the forest oor (a decomposer system) and creating a year-round pasture environment for hens to forage. By doing so, bacteria and other microorganisms pro- liferate. It is believed that these organisms likely constitute an important component of the birds’ diet, contributing protein and other nutrients, as is seen in other carion/ detritous-eating species. While the food scraps themselves provide feed for the hens, as fallen Oil Palm fruits do their ancestors, this food also becomes a medium for growing bacteria.

In the US the average individual disposes of roughly one pound of food each week. When averaged with disposal at businesses, industries and schools, communities typically dispose of roughly 500–750 pounds of food scraps per year per capita (based on statewide estimates for Vermont). Given these volumes a significant number

of hens could be fed, and a significant number of eggs could be produced, either entirely without, or with a fraction of, the grain required for a standard grain ration, thereby mitigating energy inputs in the food system and increasing producer margins. In efforts to develop regenerative food and farming systems with balanced and internalized energy equations, local economies with maximized community-based value creation and farm viability, this is an attractive proposition.

Vermont Compost Company (VCC), owned and operated by composting leader Karl Hammer, is a composting operation specializing in compost-based potting soils in Montpelier Vermont that has pioneered this practice in the US. They have been feeding hens on food scraps and selling eggs in the community for over 15 years. They began collecting food scraps from local restaurants and schools in 1998, eventually handing off their collection program to the Central Vermont Solid Waste Management District (CVSWMD). In 2016, CVSWMD delivered over 1100 tons of food scraps to VCC. VCC has fed its ock of between 600–1400 chickens—which has fluctuated somewhat over the years—with no purchased grain. The chickens produce eggs year-round, with augmented light in the winter, and have not displayed any signs of a lack of nutrition or disease.

As homesteaders we had also utilized this practice for over 10 years with success. Upon establishing Black Dirt Farm in 2014 we were eager to bring this model to scale, but had no data. Our desired flock size was 2,000 hens. We applied for a USDA SARE Farmer Grant to better understand the practice before of scaling up. The practice fits our operation for a variety of reasons. Black Dirt’s farm model is designed to increase value within the farm system through process integration that will mitigate input costs, such as hen feed or heat for the greenhouse, reducing pressure to increase revenues. By stacking functions and dovetailing value from one enterprise into the next, we aim to keep the scale of each enterprise as contained as possible, limiting the need for growth.

Our core enterprises follow the decomposer cycle, beginning off the farm when we collect food scraps. We currently collect roughly 200 containers per week from 60 entities, mostly within a 30-mile radius, but extending as much as 50 miles in some cases. We deliver roughly 15 tons a week to a partnering farm for making compost, and bring 7–10 tons to our own farm each week. Food scraps arrive at the farm at a net pro t and reduce our need for purchased feed, immediately lowering operating costs and the scale at which we must operate to be profitable. After food scraps have been blended into a compost mix and fed, they are removed from the hens for making compost. We are in the process of establishing an Aerated Static Pile system to harvest heat from the composting process to heat our 30’x100’ greenhouse and reduce labor. The composting process yields a preconditioned feed for worms, from which we make worm castings, and compost. Our farm sits at 1500’ on Stannard Mountain in the Northeast Kingdom of Vermont in a USDA Zone 3b climate, where we also undertake a variety of farm enterprises and homestead functions included in this project.

In general, small egg operations (less than 5,000 birds) are economically challenging given the high cost of feed within current production models. Feed costs can represent as much as 70% of total production costs and 30% of the retail value of the egg.   Communities everywhere generate substantial volumes of discarded food and food processing byproducts that may be cost-effective alternative feed sources, and these materials, when integrated into a composting system, may yield additional benefits. 


Project Objectives:

During year one we focused on food scrap nutritional and pathogen sampling and testing, and egg and pathogen testing, and cost tracking. During this time we scaled up our collection operations, onsite infrastructure and flock in preparation of beginning the split flock trial. With the exception of January and February 2015 we collected good data over the year and completed sampling and analysis in the fall of 2015, the beginning of our second year.

In the spring of 2015 we shifted from attempting to develop a food scrap-based ration informed by food scrap sampling, because we were unable to replicate hen foraging habits in our sampling methodology. We were struggling with a major inconsistency in our findings mid-project – Dr. Darre’s ration calculations determined that the hens could not lay productively on a diet containing more than 5-7% food scraps while our laying rate for the food scrap group was within 5% of the grain group, and at times exceeding it. With this in mind we decided to evaluate the outcomes of the food scrap feeding model against grain-fed hens instead.

 Objective 1: Evaluate nutrient content of food scraps – Partially Complete

While we did conduct much of the food scrap analysis we had proposed, we stopped this sampling and testing regime because we felt our sampling methods were not accurately reflecting the hens foraging habits or the microbial contribution to the ration that is developed in the composting system. We pivoted and applied the remaining time and budget to testing egg nutrition, tracking egg weights, and assessing egg cracking and characteristics.

Objective 2: Assess food scraps for Salmonella enteritis - Complete

Objective 3: Assess eggs for Salmonella enteritis and nutrient composition - Complete

  1. In 2015 we expanded the number of egg samples we had analyzed and collected additional data on egg weights, egg deformities and cracking, and yoke color.

Objective 4: Assess poultry housing for Salmonella enteritis - Complete

Objective 5: Assess economics of food scraps as poultry feed and monitor egg production – Complete

  1. In addition to tracking historical costs and revenues for the two split flock groups, we produced a profit and loss for our current hybridized feeding system of 300 birds, and a projected budget for a 2000 bird flock on a hybridized feeding regime.

 Objective 6: Disseminate information - Complete

  1. Produce ration recommendations and Best Management Practices – Complete

This objective was modified. We did not establish firm ration recommendations based on food scrap testing, however we were able to establish a good compost recipe and the necessary feeding rates per hen.  We produced Feeding-Community-Food-Scraps-to-Laying-Hens-in-an-Active-Composting-System-manual to help share this practice with other operators.

       2.  Host Field Day - Twenty growers will attend the field day - Complete

In October 2015 we hosted a farmer field day at our farm and then brought the group to Vermont Compost Company in Montpelier, VT. Sixteen people attended the workshop. Additionally, we presented our project and findings at three conferences (VCRD Climate Economy Conference, UVM Food Systems Summit and Vermont Organics Recycling Summit), to the 2016 UVM Farmer Training Program, 2016 Sterling College Small Enterprise class, and several high school classes, as well as directly by phone and email with at least six commercial or aspiring farmers interested in the practice, all of whom would also be adding new food scrap recycling collection services and infrastructure in their communities.

          3.   Disseminate information through media – Complete

Our farm and the work addressed in this project were covered in articles in Natural Farmer, Biocycle, Hardwick Gazette, and was featured in the 6-episode food system series ‘Local Motive’ produced by the Skinny Pancake and aired on Vermont Public Television.


Materials and methods:

Nutritional Testing – Food Scraps

Food scraps were sampled from large groups of subsamples accumulated during month long sampling periods. We proposed to analyze the food scraps for the caloric content, amino acids, calcium, phosphorous moisture, total protein, total fat, total ash and total carbohydrates, from which we would develop a feed ration.

 Nutritional Testing – Eggs

Egg samples were gathered from large subsamples of eggs collected within month-long sample periods, blended and sampled. We tested eggs for an extensive battery of nutrients, including: Amino acids, Calcium-phosphate content and ratio, Folic Acid, Cholesterol, Saturated Fat, and Omega 3 and Omega 6 fatty acids. This nutritional testing was expanded upon during the study. While total numbers of samples was small and some of the measures changed, we were still able to get a decent view of the nutritional trends in the eggs.

Pathogen Testing – Eggs

Egg samples were gathered from large subsamples of eggs collected within month-long sample periods, blended and sampled. Egg samples were analyzed for Salmonella enteritis by the Cornell Animal Health Laboratory. Enteritis species alone were screened for due to their human health implications; non-enteritis species of Salmonella were discarded.

Pathogen Testing – Hen House

The chicken coop was sampled with the environmental swabbingmethod used by the FDA to assess the presence and levels of Salmonella enteritis, “Environmental Sampling and Detection of Salmonella in Poultry Houses.” Swabs were submitted to Cornell for analysis. Enteritis species alone were screened for due to their human health implications; non-enteritis species of Salmonella were discarded.

Egg Weights – ADDED MEASURE Egg weights were taken by weighing samples of eggs during monthly sampling periods. Eggs were weighed in grams.

Yoke Color – ADDED MEASURE Egg yoke color was evaluated using the DSM International Color Fan, a 15 color scale for assessing yoke color. Egg samples were collected from large subsamples and evaluated by holding the color fan next to the yoke.

Egg Cracking and Conformation – ADDED MEASURE

Eggs with cracked or imperfect confirmation were set aside during washing and counted by group. Cracks and conformation issues were combined and tracked by incidence.

Information Dissemination

We evaluated how effective our information dissemination by the number of published articles, attendance at the field day, and attendance at presentations. Surveys were used in one presentation to assess how serious attendees were about implementing these practices. An electronic Survey Monkey survey of field day attendees had a 5% return rate and was not meaningful. An online survey of the Agricultural Service Providers in Applied Poultry Science regarding the usefulness of materials produced was not conducted due to a lack of time.

Research results and discussion:
  1. Pathogens – at the outset of this project it was established that Salmonella enteritis was the food-borne pathogen of greatest concern to animal and human health associated with this practice. This project has taken a thorough look at Salmonella enteritis and established that the risk of transmission is low. No Salmonella enteritis was found during food scrap, egg or environmental sampling on our farm or the other participating farm.
  2. Egg Productivity – Over the year the Grain Group produced 2% more eggs than the Compost Group. This does not include two months of winter data which was excluded because of a temporary stop in the project due to weather and machinery break downs. It is likely that the Grain Group out-produces the Compost Group in the winter months more significantly than indicated here. At times in the year (summer) the Compost Group produced more eggs, as much as 10% more, than the Grain Group for periods of several months.
  3. Egg Quality - Egg nutrition was similar in the Grain and Compost Groups, however there were some distinct differences that surprised us and require further inquiry.  The Compost Group had higher Folic Acid, Leucine (amino acid) and trans-fats, and lower Omega 3 and Omega 6. Protein, Calcium and Magnesium in a hybridized feeding schedule exceeded USDA baseline modestly, while Vitamin D and Potassium were lower.  Additionally, the Compost Group’s eggs were roughly 4% lighter. Yoke color on the DSM color scale (1-15 lightest to darkest) was typically 12 for the Compost Group and 5 for the Grain Group.
  4. Management Practices – We have collected good observational feedback on the management of this system to share with other growers.
  5. Ultimately this project will conclude that feeding food scraps to laying hens in a composting system is a viable practice with many potential benefits to be further explored, however there are practical challenges to this system that require further evaluation.
Research conclusions:
  1. Improved infrastructure, management practices and business modeling based on observation and data collection over 3 years. Clarified that it appears advisable in northern climates (Zone 3) to supplement winter diet with grain in order to maintain desirable productivity.
  2. Collected good discovery-phase data for establishing the viability of this practice.
    • The Practice is economically viable
    • No presence of Salmonella enteritis was found in eggs, hen manure or food scraps.
    • Egg quality and quantity are similar to grain fed hens seasonally.
  3. Reached over 200 individuals directly through conference presentations, farm tours and direct support. Additionally, articles in Natural Farmer and Biocycle Magazine reached their extensive regional and national readerships.
  4. Produced power point presentation on the product and our feeding system
  5. Produced 33-page operator’s manual ‘Feeding-Community-Food-Scraps-to-Laying-Hens-in-an-Active-Composting-System-manual,’
  6. Established link between active composting function within the diet and overall system functionality – the fact that at times the Compost Group out performed the Grain Group by as much as 10% suggests that this system is variable and can therefore be optimized.
  7. Established this as a credible practice of interest among poultry and livestock researchers and specialists. In addition to the partners participating in this project, a new project has been implemented with UVM College of Ag and Life Sciences to evaluate the presence of antibiotic resistant bacteria in food scraps.
Participation Summary

Education & Outreach Activities and Participation Summary

Participation Summary:

Education/outreach description:
  1. Feeding-Community-Food-Scraps-to-Laying-Hens-in-an-Active-Composting-System-manual – 33–page Operator’s Guide
  2. 2016 Food Systems Summit Presentation – Power Point Presentation
  3. 2016 Vermont Organics Recycling Summit presentation
  4. Natural Farmer, Winter 2015-2016
  5. Biocycle, JG Press. August 2016.
  6. Local Motive, Episode 6, February 2017. Vermont Public Television.
  7. 2015 VCRD Climate Economy Summit

Project Outcomes

Assessment of Project Approach and Areas of Further Study:

Potential Contributions

Reduction of environmental and health risks in agriculture

Feeding CFS to hens will reduce energy inputs and emissions associated with importing grain and landfilling discarded food materials. The energy costs for importing grain can be significantly or entirely mitigated, while there is an increase in equipment operation. Studies comparing similar collection programs for composting have found composting to reduce emissions associated with landfilling. For a project of this scale, in which we currently feed 300 hens on 7-8 tons of food scraps per week, we estimate an emissions reduction equivalent to not burning roughly 30-39,000 gallons of gasoline annually. Vermont is estimated to mitigate emissions equivalent to not burning 12 million gallons of gas annually by composting food scraps (Alliance for Climate Action).

Salmonella enteritis is a public health concern in egg production, and in the case of chicken meat, has not been limited to large-scale commercial production. A small study in Pennsylvania found levels of Salmonella in chicken sold at farmers’ markets to be substantially higher than those purchased in grocery stores. This project worked to help ensure that feeding food scraps to laying hens does not increase the risk of Salmonella enteritis to the public and found no presence of Salmonella enteritis.

Prevention of agricultural pollution

This system promotes the composting of poultry manure. In order to effectively compost manure and achieve the desired composting activity desired from a feeding perspective, adequate carbon is supplied to sequester nitrogen in the form of microbial biomass, preventing leaching. Additionally, maintaining aerobic conditions mitigate methane formation.

Reduction of costs, increase of net farm income

Feed costs represent as much as 70% of total egg production costs across a wide range of scales. Feeding food scraps can decrease feed costs, and improve net returns. In some cases farmers not only realize cost savings, but also new income for collecting food scraps. A 50-75% reduction in feed costs for a flock of 2,000 birds amounts to $30-42,000/ year, and new revenue associated with compost sales. Additionally, a farm seeking further integration and value realization can capture heat from the compost processing to mitigate the use of purchased fuels for heat generation.

Conservation of soil, water quality, and natural resources

This feeding system produces compost from uneaten food materials, manure and bedding. This can benefit both the farm and the broader, local food system. The provision of compost to field or garden soils benefits overall soil health. Healthy soils prevent runoff and sequester carbon, as well as grow more food. This can also mitigate the use of synthetic and mined inputs, and toxins, such as fungicides. This conserves finite resources, such as rock phosphate and fossil energy, and protects water systems and aquatic species from runoff.

Enhancement of employment

By increasing the economic efficiency of egg production on small farms, the overall egg market will grow and employment in the space will follow. Internalizing CFS collection in the local economy will not only create jobs on the farm, but will include roles in collection. New jobs may occur through farm businesses or traditional waste haulers.

Improved quality of life

Increasing profitability for farmers at a small-scale can improve farm-family quality of life. Smaller operations can be more family-friendly, offering more opportunities for the whole family to be involved. Additionally, communities prefer smaller operations, as their discharges and emissions in all forms tend to be smaller and less impacting.

Retained Community Wealth

By capturing food scraps for feeding and composting nutrients and dollars that would otherwise be lost from a community food system are captured, increasing the resource abundance and economic vitality of the community. Farms can increase the cycling and further retention of the economic value by making purchases from locally owned businesses.

Expanded Interest

Through this project poultry researchers and specialists have now become engaged in research on this topic, and ultimately feel it is a promising opportunity. This is turn has helped legitimize the practice and attracted additional interest. This project has spurred a project at the University of Vermont to assess the presence of antibiotic resistant bacteria in the food scraps and their fate in this feeding system. We hope these projects continue to gather interest and expand the circle of inquiry.

Informed Policy

With growing and diversifying agriculture and resource recycling industries, Vermont agency policy makers are grappling with issues of oversight and regulation, jurisdiction, and the implications of the Food Safety Modernization Act. This project has allowed us to contribute meaningful content for these discussions.

Future Recommendations

  1. Assess composting feeding system ration and evaluate role of composting activity in the ration and egg nutritional content.
  2. Validate production and cost data in bigger flock size over full year.
  3. Validate Salmonella enteritis results and expand scope of pathogens of interest.
  4. Develop Best Management Practices for rodent and other vector mitigation and control.
  5. Investigate operational system efficiencies for managing materials, feed conditioning, and feeding.

Information Products

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.