culling male chicks

Sustainability, animal welfare, and Easter eggs

As many people are getting ready to color their Easter eggs, now is an excellent time to discuss eggs – specifically their sustainability and animal welfare concerns. Eggs are a low-cost source of protein and other nutrients. They are an important and well-loved part of many people’s diets. Eggs are also more sustainable than most other animal-sourced foods. But some practices in egg production are concerning when it comes to animal welfare. A philanthropic group now aims to remedy one area of concern. (Content warning: This article discusses culling of male chicks.)

Easter eggs
Colorful Easter eggs are just one of many ways that eggs are an important part of cultures across the globe. My Babcia (grandmother) used foods like beets, onion skins, and cabbage to color Easter eggs in beautiful muted shades.

Calling for improvements in chick welfare

The Foundation for Food and Agriculture Research (FFAR) has a new initiative called the the Egg-Tech Prize. This project aims to find solutions to one major welfare issue – unneeded male chicks. FFAR is offering up to $400,000 per project, with up to 5 projects selected. You have a little time to consider ideas – applications are due on May 15, 2019.

Why does this matter? Obviously, male chicks are not useful for laying eggs. But male chicks from an egg-laying breed can’t be raised for meat due to low meat quality and slower growth than chickens that are specifically bred for meat.

culling male chicks for our Easter eggs

The current industry standard involves euthanizing male chicks by grinding, suffocating, or other means. Such work can take a psychological toll on those who carry out the euthanasia. Even if you raise backyard chickens, your chicks likely come from a facility that euthanizes male chicks. Trade group United Egg Producers pledged to stop these practices, and instead determine the sex of eggs before they hatch. The problem is, there still isn’t a good method to do that.

Even if you aren’t concerned about the welfare of chicks, the distress or pain they may experience as they are euthanized, or the ethical issue of creating a life just to immediately kill it, there’s an argument to be made for making a sustainable product even more sustainable. Culled male chicks end up as chicken by-product meal in pet food, or as fertilizer. They don’t go entirely to waste, but they could be put to better use. For example, male eggs could be diverted to vaccine production.

Note that culling of male chicks isn’t the only welfare concern associated with egg production. Other concerns include keeping layers in cages, but cage-free eggs can lead to other problems, and have a higher cost.

Incredible eggs

As shown in the below Protein Scorecard by the World Resources Institute, eggs are inexpensive (2.5 to 4 cents per gram of protein) and have relatively low impact on the environment. Globally, eggs take less water to produce than roots and tubers, dairy, poultry, farmed fish, pork, or beef. Egg substitutes are getting better all the time, but these highly-processed foods have their own disadvantages.

As FFAR points out, “for the 6 billion laying hens hatched each year worldwide, a similar number of male chicks are produced that never make it to market.” Finding ways to use (or even prevent) unneeded male chicks could have quite an impact, making eggs even less resource intensive.

protein scorecard
Protein Scorecard from the World Resources Institute.
sustainability of animal and plant foods
Resource use for foods on a per-protein basis from the World Resources Institute.

Many cultures enjoy eggs

In addition to being high-protein and sustainable, eggs are also delicious and versatile in cooking. These factors make eggs an incredibly important source of protein, globally. Many, many countries around the world feature eggs in traditional dishes. Groups like Heifer International advocate eggs as an important way to provide nutrition to children and help pull families out of poverty.

As we approach Easter, I’d be remiss if I didn’t mention my favorite, Polish Easter Soup, also known as bread soup or white barszcz. Its tangy sour taste can be provided by vinegar or by fermented flour. Easter soup is a delicious way to enjoy Easter eggs! For many years, I have made a solid vegetarian Easter soup, though no one sells a decent vegetarian kielbasa!

Aside from holidays, my family relies on eggs as a protein source that we all enjoy. I’d feel a little better about our frequent egg dinners if culling male chicks was no longer necessary.

Alternatives to culling male chicks

How can this problem of unneeded male chicks be solved? Some have proposed Dual-purpose chickens as alternative to culling. It’s an attractive idea, but such dual-purpose chickens are not as efficient as single-purpose chickens. They are slower to grow, and lay fewer eggs, decreasing the sustainability of both egg and chicken meat production.

Various alternative culling methods have been proposed, but none are ideal. For example, 100% carbon dioxide produces a relatively quick death, but chicks are still in distress. It’s not much of an improvement, and the destined-to-die male eggs still take up space in incubators.

Screening the eggs before hatching would be better, though can be expensive, up to 5 cents per egg. Light can be used to determine whether an egg is fertilized. Light may also be a way to determine if an embryo is male or female. Researchers have found that male chick embryos are more opaque than female chick embryos.

Testing DNA or other biomarkers in eggs is the solution United Egg Producers was hoping for, allowing male eggs to be diverted to other purposes or euthanized before they hatch. One such method is being rolled out in Germany.

Could genetics or biotech help?

As a geneticist, my first thought after reading about the Egg-Tech Prizewas – surely there’s a way to solve this with genetics-related methods. Biotech doesn’t solve every problem, but it’s a really useful tool!

A quick aside – chicken sex is determined by chromosomes, just as in mammals. However, while mammals are XX female and XY male, chickens and other birds are ZW female and WW male. Of course, this is a major simplification of sex, particularly when we are talking about humans. View an infographic with just some of the complexity at Beyond XX and XY: The Extraordinary Complexity of Sex Determination.

Fluorescent eggs

Researchers at Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO) are developing eggs that emit red fluorescence when viewed under a special light (I used similar technology in a corn breeding program). Read about this idea in How CRISPR could save 6 billion chickens from the meat grinder.

The researchers put the gene for red fluorescence on the W chromosome provided by the mother chicken. Males would get that genetically engineered W plus a regular W from their father. Female chickens would get a Z from their mother and a regular W from their father. The resulting female eggs would not have the fluorescence gene.

While this solution is interesting, I am not as optimistic as the researchers that such chickens would escape regulation. Any egg production companies wanting to use this technology (or any technology that involves DNA or biomarkers) would have to install new screening systems, a significant barrier to adoption. And, you still have a ton of male eggs that need to be used quickly before they develop into chicks or spoil.

Who needs males, anyway?

Parthenogenesis is the development of an embryo from an unfertilized egg. While rare in birds, there are examples of virgin chickens and turkeys laying eggs that develop into chicks. Perhaps an egg laying chicken breed could be developed that would lay parthenogeneic female eggs when given some sort of inducer, but otherwise would lay unfertilized eggs. There would both be no unwanted male eggs and no need for males at all!

culling male chicks for our Easter eggs

Of course, this is much easier said than done. Plants are more cooperative when it comes to apomixis (parthenogenesis in plants). However, there are examples of parthenogenic vertebrates. For example, the whiptail lizard is a polyploid obligate parthenogen that has all female offspring.

One point in favor of this idea is that “genomic imprinting is believed to be absent in birds“. In other words, the epigenetic programming that happens in mammal embryos isn’t an issue for chickens. Another point in favor of this idea is that inducible parthenogenesis has been in development for stem cell research, so compounds are being identified that could induce parthenogenesis, such as valproic acid. Ideally, an inducer could be applied in feed or along with vaccines to reduce need for additional handling of the birds.

I don’t plan to apply for the Egg-Tech Prize, so feel please free to research and pursue this idea 😉 I’d just be happy to find eggs that don’t require culling male chicks. I’ll hard boil the eggs, dye them with onion skins for Easter, and then make vegetarian Polish Easter soup!


  1. What I’m really curious about is when we can start applying cellular agriculture concepts to eggs. Just grow the eggs directly from stem cell lines, no need for any chicken involvement at all (at least not in production – presumably we’d still breed them for traits and nonlethally harvest cells for a while until we round out our understanding of their genetics a lot more).

    Between cellular agriculture and tissue cultures, bioreactors, and genetic engineering of microbes to produce proteins and nutrients, food production in 100 years is going to look really interesting, assuming climate doesn’t send us into civilizational collapse.

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