Since January this year, Norwaste, in collaboration with Stakeholder AS and Den Stolte Hane, has been working to explore how spent laying hens can be better utilized as a resource.
The project was initiated in response to the fact that around 3.5 million laying hens – equivalent to approximately 6 500 tonnes of biomass – are culled each year when egg production ends. Today, most hens are euthanized on farms and classified as Category 2 animal by-products. This means they are transported for processing after culling, and the resulting material is primarily used for the production of biofuel and cement.
Through this project, we wanted to explore whether there is potential for better resource utilization that could create higher value, reduce costs for egg producers, and potentially deliver greater climate benefits.
Comprehensive data collection across the entire value chain.
Since its launch, the project has aimed to establish a solid knowledge base on the current situation and potential alternative solutions. This has involved extensive data collection through meetings with key stakeholders across the value chain, engagement with egg producers, dialogue with biogas operators, and regular collaboration with project partners. The work has provided valuable insights into current practices, challenges, and opportunities for improved resource utilization.
Biosirk plays a central role in the current system, where spent laying hens are collected and processed together with other animal by-products. The material is ground, sterilized, and separated into fat and protein meal, which are primarily used for energy production and industrial applications.
An important part of the project has been visiting farms to understand how current solutions work in practice. During visits to egg producers, the project team gained first-hand insight into daily farm operations and how the culling of laying hens is managed. Producers explained that they previously had the option of sending hens for slaughter, but that this is no longer available. Today, the hens must be euthanized on-site, typically by gassing, and then transported for further processing.
Several producers point out that the current solution of delivering hens for processing is costly. Expenses related to both culling and transportation make the end-of-lay process a significant cost item, leading to calls for more economically viable alternatives. At the same time, producers express a desire to see the birds utilized in higher-value applications, ensuring that more of the resource potential is retained.
To better understand the potential for alternative solutions, the project team also engaged with and visited several biogas facilities. The focus was on gaining insight into pre-treatment technologies and sanitization processes for different types of feedstocks, as well as assessing the extent to which existing facilities could handle materials such as spent laying hens.
Visit to the Mjøsanlegget Biogas Facility
Visit to the Ecopro Biogas Facility
It has been essential for the project team to learn from a diverse range of facilities involved in the treatment of biological waste in Norway in order to understand which combinations of pre-treatment and sanitization technologies would be required to handle spent laying hens. This has provided valuable insight into the technical and operational requirements for potential future solutions.
The treatment facilities varies in both which technical solutions that have been chosen and which biomass feedstock the facilities can receive. It can bepractical challenges related to factors such as particle size and the handling of bones and feathers, in addition Category 2 animal by-products is are subject to stricter sanitization requirements than feedstocks such as food waste and livestock manure.
Several potential pathways identified
The project identified several alternative pathways for managing spent laying hens, each with different technical, regulatory, and economic requirements. Regulations play a crucial role in determining which solutions are feasible, as on-farm euthanasia by gassing results in the material being classified as a Category 2 animal by-product, limiting its potential uses compared with slaughtered animals, which are classified as Category 3 animal by-products and can be utilized in a wider range of applications.
The pathways consist of different combinations of on-farm euthanasia by gassing or slaughter, handling the material as either a Category 2 or Category 3 animal by-product, and subsequent processing through rendering, biogas production, or animal feed applications. The project also considered slaughter for use in human consumption.
What the pathways have in common is that they are all considered technically feasible and compliant with current regulations. At the same time, they vary significantly in terms of complexity, infrastructure requirements, and cost levels.
The current management of spent laying hens has developed for valid reasons, but we want to explore whether there are alternative solutions that make better use of these resources. We are now assessing the economic viability and climate impacts of different pathways, ranging from biogas production and animal feed to human consumption. The goal is to identify new sustainable solutions that create value for both society and the industry.
Getting closer to a conclusion
For several of the alternatives, there is currently limited experience and data available, which makes the assessments subject to uncertainty. As a result, extensive work is now underway to collect cost data and develop comparable analyses across the different pathways.
Although the project has identified several realistic alternatives, further analysis and evaluation are still required before final conclusions can be drawn. The analyses will continue and be completed during autumn 2026, with the results to be presented in the final project report.
