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Chick culling: What is it, what are the methods & is it cruel?

Photo: Andrew Skowron / We Animals Media

The term “culling” is a sanitized way of referring to the process of removing chickens from a flock and killing them. The shocking mass killing of day-old male chicks as part of the egg production industry is perhaps one of the best-known examples of culling. Beyond these male chicks, however, millions of other birds are annually culled from flocks around the U.S. for a variety of different reasons, using an array of different methods.

What is culling a chicken?

Culling a chicken is another way of saying that a chicken is being removed from a flock and killed. Chickens that are culled are typically killed on the farm rather than being shipped to a slaughterhouse or outside facility. Removing chickens from the flock by killing them is performed both routinely and in response to emergency situations. For example, during the height of the coronavirus pandemic in 2020, millions of chickens were killed in order to depopulate farms, simply because slaughterhouses were not open or operating at a high enough capacity to slaughter them. Many of these chickens were smothered using foam or poisoned en masse with carbon dioxide.

The ongoing outbreak of avian influenza on farms across the United States is another situation that is leading to millions more chickens being killed. As of early December 2022, more than 52 million chickens and other birds have been killed as part of the response to the current outbreak of avian flu. The current outbreak is the worst in the nation’s history, with 46 states being affected.

Why do farmers cull chickens?

The largest expense for most chicken farms is feed, so if a bird is not going to make the farmer more money than they are spending on feed for that individual then the chicken is likely to be killed. There are a number of different reasons why a chicken may be judged as not being economically beneficial, including age, sex, or injury.

  • Typically, layer hens are killed after about a year of laying due to a decrease in their productivity. Because these hens are raised as a group with other birds of the same age, productivity can be evaluated on a group basis and not based on the individual bird. For this reason, even if an individual bird is still producing well they may still be culled simply because their cohort of hens has dropped in productivity. During that year a single hen may lay 300 eggs or more, which takes a massive toll on her body. Fractures of the keel bone, which runs along the underside of the birds’ cavities, are common in laying hens, as the eggs are both very large and require a lot of the calcium that the mother hens consume, leading to weaker bones.1
  • When a staff member notes that an individual bird seems ill or is seriously injured, for example unable to walk, that bird is likely to be removed from the flock and killed.
  • Just a few decades ago, most chickens were raised both for their egg production and their eventual slaughter for meat. Today, however, there are two different kinds of chickens: those raised for their meat and those raised to produce eggs. In chickens raised for meat, also known as “broiler” chickens, there is no differentiation based on sex, as these chickens are not generally allowed to live long enough to produce eggs. When it comes to birds raised for laying eggs, male chicks are unable to lay eggs, so serve no purpose in the industrial system that has produced them. Male chicks are routinely killed before they can grow to be more than a few days old.

Why aren’t male chicks suitable for meat?

In the 1940s a contest was held by the USDA and a grocery store. The goal was to produce the largest chicken, who consumed the least amount of feed and had the best quality of meat. Since that time chickens have endured intense breeding programs intended to increase their profitability. Chickens raised for meat have grown larger as a result, and now have massive breasts and huge thighs, consuming about three-quarters less feed than their forefathers while growing at a much faster rate. Laying hens, by contrast, have been bred to produce an ever-increasing number of eggs.

Today’s broiler chickens are so much larger and grow so much faster than the breeds used to lay eggs that raising the male chicks of laying breeds would not only fail to produce a profit for the industry but actually end up costing them money, as the birds would cost more to feed than they would sell for.

How do farmers cull chickens?

There are several different ways that chickens are killed once they are removed from the flock. The method used depends on several factors, including the age of the chicken, the capacity and size of the farm, and the reason that they are being culled. If birds are being killed in a large number, for example to prevent the spread of disease or for depopulation, the method used is likely to be different than if a few birds are being killed at one time due to injuries.


Maceration (also called “grinding,” “shredding,” or “mincing,”) is a common practice within the egg industry and is used as a means of dispatching day-old male chicks that are viewed by the industry as a by-product due to their inability to lay eggs. The process typically consists of placing the chicks onto a conveyor belt that ends in a large grinder into which the unsuspecting, fully conscious chicks fall and are torn apart. The practice is regarded as humane by those within the industry, but due to increasing outcry from the public, alternatives are being pursued to avoid the bad optics associated with the mass grinding of day-old chicks.2


Within the chicken production industry, asphyxiation goes by the term ventilation shutdown. There are several different types of ventilation shutdown: sealing off airflow alone, sealing off air and adding heat to induce heat stroke more quickly, and adding carbon dioxide which deprives the chickens of oxygen. This method of killing chickens tends to be used on a larger scale and has been employed in response to the ongoing avian flu outbreak in the United States. Millions of birds have already been killed as a result of the ongoing outbreak using this method.

Cervical dislocation

Cervical dislocation consists of snapping an individual chicken’s spinal cord. This method of culling birds is used when only a few birds are being killed at a time and is considered humane by the industry when performed by trained personnel. In the UK and the EU, only birds under 3 kilograms can be killed using this method; there is no such provision in the United States.


Electrocution is used both to stun birds prior to killing them in slaughterhouses and to stun or kill birds that have been culled from the flock. There are three different methods of electrocuting chickens: water-bath, head-only, and head-to-body. Water-bath methods tend to be used only for large-scale killing, and are also the common form of stunning in U.S. slaughterhouses. Head-only electrocution is just a stunning method and cannot kill birds as a method on its own, but both head-only and head-to-body electrocution are used in both large-scale killing and individual slaughter.3


Suffocation, such as by filling the cages in which the chickens are housed with foam, is another way that chickens are killed on a large scale. This method is considered a viable alternative despite research showing that birds killed using foam took longer to stop moving and produced more stress hormones than birds killed using other methods such as carbon dioxide exposure.4

Is chick culling cruel?

Yes, chick culling is cruel. It’s hard to imagine another industry in which living beings are bred with the knowledge that half of the resulting offspring will be killed. Maceration, in which chicks are fed into a grinder, is still the method recommended by the American Veterinary Medical Association. However, other methods of killing day-old chicks, including using carbon dioxide or negative pressure, are gaining traction due to consumer backlash surrounding maceration.5

Is chick culling illegal?

Chick culling is legal and standard practice in the United States. However, this isn’t the case everywhere; France and Germany have both taken steps to ban the culling of chicks.

Can new technologies eliminate chick culling?

Promising new technologies are emerging that could eliminate the need for chick culling. They depend on being able to determine the sex of the chick before the egg has hatched. If the chick is going to be a male then the egg will be discarded long before it hatches. Though this technology is already being used on a large scale in several European countries, in large part due to pressure from animal welfare organizations including Farm Forward, U.S. egg producers have been slower to incorporate it into their systems of production due to the high cost of the equipment.

In December 2022, news broke that a team of Israeli scientists used recombinant DNA technology to genetically engineered hens who lay eggs that only produce females. While this development has the potential to halt the culling of male chicks, it does nothing to ease the suffering of the millions of females who live in the wretched conditions of egg factory farms.


Every year millions of chickens are removed from chicken flocks and killed on farms across the country. Though there are many reasons for this, including preventing the spread of disease among immunocompromised birds, reducing the population due to overloaded slaughterhouses, injury to the birds, or simply the fact that many chickens bred for egg production are born male, there is one fundamental reason at the heart of them all: the industry wants to make money and the chickens that won’t contribute to that end goal are culled.



Anja B. Riber, Teresa M. Casey-Trott, and Mette S. Herskin, “The Influence of Keel Bone Damage on Welfare of Laying Hens,” Frontiers in Veterinary Science (February, 2018),


Ellen C. Jongman and Andrew D. Fisher, “Euthanasia of Laying Hens: An Overview,” Animal Production Science 61, no. 10 (March, 2021): 1042–1047,



EFSA Panel on Animal Health and Welfare, “Killing for Purposes Other than Slaughter: Poultry,” EFSA Journal 17, no. 11 (November, 2019),


Shailesh Gurung et al., “Depopulation of Caged Layer Hens with a Compressed Air Foam System,” Animals 8, no. 1 (January, 2018),



Xi Wang, et al., “Evaluation of Euthanasia Methods on Behavioral and Physiological Responses of Newly Hatched Male Layer Chicks,” Animals 11, no. 6 (June, 2021),