Can Spent Hemp Biomass Safely Become Chicken Feed?

Hemp producers can extract valuable cannabinoids from flowers and leaves, but the process leaves behind a substantial quantity of plant material. Known as spent hemp biomass, this residue may retain protein, fiber, minerals, fatty acids, and cannabinoids even after extraction. Most of it currently has limited commercial value and may be composted, stored, or discarded.

Finding another market for this material could improve the economics of hemp processing while reducing agricultural waste. Livestock feed represents one possible destination, particularly when conventional feed ingredients become expensive or difficult to source. However, putting hemp biomass into the food chain raises questions involving animal health, productivity, meat quality, and residual cannabinoids.

A new study¹ published in Poultry Science offers one of the clearest examinations of these tradeoffs in chickens. Researchers found that spent hemp biomass could be incorporated into broiler diets at a relatively low concentration without compromising growth or meat quality. Once the concentration reached 10% or more, however, the disadvantages began to outweigh the potential benefits.

Why Hemp Waste Is Being Considered as Animal Feed

Spent hemp biomass is primarily composed of the leaf and flower material remaining after cannabinoids such as CBD have been extracted. Although the most commercially desirable compounds have already been removed, the remaining biomass is not nutritionally empty.

Previous research has found that spent hemp biomass can possess a nutritional profile comparable to alfalfa. It may therefore have potential as a lower-cost feed ingredient, especially in regions where hemp is processed near livestock operations. Local reuse could reduce disposal requirements and transportation distances while providing hemp processors with an additional revenue stream.

This concept reflects a broader effort to develop sustainable and circular food systems. Instead of treating the primary extracted product as the plant’s only valuable output, processors can look for appropriate uses for each remaining material. Recent research into underused hemp biomass has similarly identified possible applications in packaging, coatings, agricultural products, and other renewable materials.

Animal feed presents a particularly demanding use case. A material may be nutritious in isolation but still interfere with digestion, metabolism, growth, or the characteristics of meat and other animal products. Residual CBD and THC also create food-safety and regulatory questions that do not exist when the same biomass is used in construction materials or compost.

How Researchers Tested Spent Hemp Biomass in Chickens

The study involved 200 Cobb-500 broiler chicks beginning at five days of age. The birds were divided among 20 pens and assigned to one of four corn and soybean-based diets for 42 days. Their feed contained either 0%, 5%, 10%, or 20% spent hemp biomass.

The diets were designed to be isocaloric and isonitrogenous, helping researchers compare the effects of hemp inclusion without intentionally giving one group more energy or protein than another. Feed consumption, body weight, and feed conversion were monitored during the trial. The researchers also evaluated carcass characteristics, breast meat quality, fatty-acid composition, internal organs, adipose-tissue gene expression, and corticosterone deposited in feathers.

Feather corticosterone was included as a potential measure of chronic stress. Unlike a blood sample, which may reflect a short-term response to handling, hormones incorporated into growing feathers can provide information about exposure over a longer period.

Five Percent Emerged as the Practical Threshold

The birds continued eating their feed regardless of how much spent hemp biomass it contained. This is important because it suggests that outright feed refusal did not cause the poorer results at higher concentrations.

The 5% diet did not reduce body weight or worsen feed conversion, meat quality, or the nutritional profile of the breast meat. Based on those measurements, the researchers concluded that an inclusion rate of up to 5% may be feasible for broiler chickens.

That conclusion requires some qualification. All three hemp-fed groups experienced more pasty vent than the control group. Pasty vent occurs when fecal material accumulates around a chick’s vent and can be associated with digestive disruption. The researchers proposed that changes to the gut microbiota might be involved, but they did not analyze the microbiome. The biological cause therefore remains uncertain.

The results should not be interpreted as evidence that producers can begin replacing 5% of commercial poultry feed with any available hemp residue. Spent biomass can vary according to the hemp cultivar, plant parts, extraction method, storage conditions, nutrient composition, and quantity of cannabinoids left behind. A safe concentration for one standardized batch may not transfer directly to a materially different product.

Higher Concentrations Reduced Poultry Performance

The 10% and 20% diets produced a poorer feed conversion ratio during the first three weeks of treatment. Feed conversion measures how efficiently an animal converts feed into body mass. A higher ratio means more feed is required to produce the same amount of growth, directly affecting the economics and environmental footprint of poultry production.

Because feed intake did not decline, the chickens were consuming feed but using it less efficiently. The study suggests several possible explanations, including the biomass’s fiber content, mineral balance, residual cannabinoids, and interactions between those components.

The negative effect was greatest in the 20% group. At the end of the trial, these birds had smaller breast muscles and lower concentrations of triglycerides and total fatty acids in breast tissue. The relative weights of the liver and brain also increased as hemp inclusion rose, although the absence of histological analysis prevented the researchers from determining whether these changes reflected tissue damage or another physiological adaptation.

The practical distinction is straightforward. A byproduct does not make feed more sustainable if farmers must use more of it to produce less meat. Any environmental savings from waste diversion could be offset by poorer feed efficiency, longer production requirements, or reduced marketable yield.

Too Much Hemp Biomass Changed the Meat

High inclusion affected more than the size of the birds. Breast meat became progressively more yellow as the concentration of spent hemp biomass increased. The 10% and 20% treatments also experienced greater drip loss, indicating a reduced ability to retain water after processing.

Birds receiving the 20% diet produced breast meat with greater shear force, meaning it was less tender. This group also had lower proportions of unsaturated fatty acids and higher proportions of certain saturated and bacteria-derived fatty acids than birds receiving lower hemp concentrations.

Changes detected in abdominal adipose tissue supported the idea that the highest dose affected how the chickens processed fat. Genes involved in fatty-acid transport and oxidation became more active in male birds receiving the 20% diet. This sex-specific response illustrates why a feed ingredient cannot be evaluated solely by examining appetite or final weight.

At high concentrations, spent hemp biomass affected several connected systems:

• Feed conversion and finished body weight
• Breast yield, tenderness, color, and water retention
• Fatty-acid deposition and lipid metabolism
• Feather corticosterone as a possible chronic-stress indicator

Animal Tolerance Does Not Resolve Food Safety

The most important unanswered question concerns cannabinoid residues. The researchers did not measure CBD or THC in edible tissues, despite recognizing that this information is essential to regulatory approval. They also estimated CBD intake from earlier biomass measurements rather than measuring its concentration in the completed diets.

Research across livestock species has produced mixed findings on whether cannabinoids transfer into meat, milk, fat, or eggs. A 2026 review of hemp in livestock feed notes that results depend on the animal, hemp product, dose, tissue, and withdrawal period. The absence of an obvious health effect in an animal does not establish that food derived from that animal meets acceptable residue limits.

Spent hemp biomass also differs from hempseed meal. Hempseed meal comes from processing seeds for oil, while spent biomass from CBD extraction generally contains leaves and flowers where cannabinoids are concentrated. Oregon State University notes that spent hemp biomass has not been permitted for food animals in the United States, even though hempseed meal received a defined pathway for use in laying-hen feed in 2025.

This distinction matters for both regulators and consumers. Approval of one hemp-derived ingredient does not automatically establish the safety of another. Each material requires a defined composition, manufacturing standard, intended species, maximum inclusion rate, and evidence addressing residues in human food.

A Potential Market That Requires Standardization

The study’s most useful contribution is not simply that 5% worked while 20% did not. It demonstrates that spent hemp biomass behaves like a functional feed ingredient with a dose-dependent biological effect, not like an interchangeable source of generic plant fiber.

Commercialization would require processors to produce consistent material. Variability in cannabinoid extraction could leave one batch with substantially more CBD or THC than another. Moisture, contamination, nutrient density, and particle size would also need to be controlled. Feed manufacturers would then need reliable testing and labeling so that inclusion rates could be calculated accurately.

Further trials should measure cannabinoid concentrations in the prepared feed and edible tissues, analyze the gut microbiome, inspect organs histologically, and evaluate whether a withdrawal period reduces residues. Larger studies under commercial production conditions would also be needed to confirm whether the apparent 5% threshold holds across different birds and biomass sources.

Spent hemp biomass may eventually give cannabinoid producers access to a meaningful secondary market while helping poultry operations source local nutrients. This study shows that the concept has merit, but it also draws a clear boundary around the opportunity. Low-dose incorporation may prove useful. Treating hemp waste as a bulk feed replacement could sacrifice productivity, meat quality, and animal welfare in pursuit of sustainability.

References:

^{1. Parker, N. B., Hermes, J., Irawan, A., Pearce, C., Ferschweiler, D., Ates, S., & Bionaz, M. (2026). Spent hemp biomass in broiler diets: Effects on performance, meat quality, expression of genes in internal adipose tissue, and corticosterone in feathers. Poultry Science, Article 107692. https://doi.org/10.1016/j.psj.2026.107692}