Infertile hatchery eggs show potential as broiler feed ingredient

Infertile eggs discarded by poultry hatcheries could provide a protein-rich feed ingredient for broilers, cutting waste and potentially making poultry production more sustainable, according to a new scientific review.

Turning the eggs into feed could reduce reliance on soybean meal and fishmeal while creating value from a hatchery by-product that would otherwise be thrown away. Replacing some soybean meal could also reduce the environmental footprint of broiler diets, although researchers say a full environmental assessment of infertile egg meal is still needed.

Researchers from Universitas Diponegoro, Indonesia’s National Research and Innovation Agency and Universitas Brawijaya examined evidence published between 2006 and 2026 on the nutritional value, processing and feeding of infertile egg meal.

Their review, published online in Food and Feed Research, covered 36 papers selected from an initial pool of 68. Overall, the studies suggest processed infertile eggs could support broiler growth, nutrient digestibility and intestinal health. However, inconsistent nutrient content and the risk of contamination remain significant barriers to commercial use.

Between 5% and 20% of eggs placed in incubators may be infertile, according to studies cited in the review. Hatcheries can identify some through candling, which involves shining a bright light through the shell to look for signs of embryo development.

Candling is generally carried out between days seven and 10 of incubation. However, checking large numbers of eggs takes time, so some infertile eggs remain in the incubator until eggs are transferred to the hatcher at day 18.

Once an egg has been placed in an incubator, it cannot be sold for human consumption under European Union marketing rules. Infertile eggs therefore have little or no economic value, despite containing protein, fat, vitamins, minerals and essential amino acids.

Nutritional value varies widely

The nutritional value of infertile egg meal depends heavily on how it is processed. Across the studies, crude-protein content ranged from 31.5% to 50.4%, while crude fat ranged from 26.9% to 38.7%. Metabolisable energy ranged from 3,950 to 5,668 kcal/kg.

One study spray-dried egg white and yolk at 55°C without adding other ingredients and produced a meal containing 43.5% crude protein. Another oven-dried the eggs at 75°C and reported a protein content of 50.4%.

By comparison, researchers who added wheat flour and palm oil before oven-drying the mixture at 70°C produced a meal containing 31.47% crude protein. Ingredients such as wheat flour or rice bran can absorb moisture and speed up drying, but they also dilute the egg’s nutrient content and must be allowed for when formulating diets.

Infertile egg meal generally contains less protein and lysine than soybean meal or fishmeal, but considerably more fat and energy. In one comparison, whole discarded egg meal contained about 34% protein and 26% fat, with an energy content of 18.1 MJ/kg on a dry-matter basis. Soybean meal contained about 46% protein, less than 1% fat and 11.2 MJ/kg.

Broiler trials report performance benefits

Several studies included infertile egg meal at up to 8% of the diet without harming broiler growth. In one 2026 trial, adding egg meal at 5% replaced up to 14% of the soybean meal and improved weight gain, feed-conversion ratio and the use of protein, fat and calcium.

Other experiments used infertile egg meal in place of fishmeal. Including it at 5% maintained broiler growth without harming blood measurements, immune-organ development or breast-meat and leg-bone characteristics.

In another trial, an 8% inclusion replacing some of the maize and soybean meal improved feed intake, weight gain, feed conversion and nutrient digestibility. Other studies linked egg meal with better digestive-tract development, antioxidant activity and intestinal structure.

But higher inclusion levels may bring drawbacks. Feeding egg meal at 7.5% or 10% raised blood triglyceride and cholesterol concentrations in one study, while an 8% inclusion increased abdominal-fat deposition in another. The researchers linked these effects to the meal’s high fat and energy content.

More protein in the diet may also mean more nitrogen is excreted. One trial recorded higher ammonia concentrations in litter from birds receiving infertile egg meal, despite improvements in protein digestibility.

Processing and safety remain obstacles

Infertile eggs can be freeze-dried, spray-dried or oven-dried to make a powder that can be mixed into feed. Oven-drying is the cheaper option, but any processing system must kill pathogens without damaging too much of the egg’s nutritional value.

Hatchery eggs may carry Salmonella, Escherichia coli and Clostridium. Mycotoxins originating in breeder feed may also pass into the eggs. Heat treatment can reduce the microbial risk, but the finished meal can be contaminated again during cooling, packaging or transport.

Commercial production would therefore need standardised processing, traceability and strict safety controls. Regulations also vary between countries, with some prohibiting hatchery waste in animal feed and others allowing heat-treated material under specified conditions.

The researchers stressed that the evidence remains limited, with no long-term commercial validation and many of the studies coming from a small number of research teams. Further independent trials are needed to establish safe inclusion rates, processing standards, costs and the overall environmental impact before infertile egg meal can become a mainstream broiler ingredient.

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