How the chicken you eat grew 400% in size in 50 years

The intention was to create a chicken with enormous thighs and breasts, with layers and layers of meat, capable of feeding an entire family for a minimum cost.

In 1946, at the end of World War II, the US government teamed up with a company to establish a contest that changed the global poultry industry forever.

The Chicken of Tomorrow Contest invited farmers and breeders from all over the country to develop, through genetic selection, a broiler chicken with the ability to grow faster and also have the best quality meat possible.

“With the competition they wanted to produce birds that could quickly gain muscle mass and that could be slaughtered at an early age,” explained to BBC Mundo Richard Thomas, an expert in bird archeology at the University of Leicester, UK.

The North American country sought to meet the high demand for protein as a result of the birth boom of the time. In addition, the war had caused a rationing of red meat, which was destined to feed the soldiers at the front.

But back then, the chicken was just a scrawny animal, raised mostly for eggs and taking about four months to grow.

In just over half a century, according to a University of Alberta study published in 2014, the average size of a broiler chicken increased by 400%.

Martin Züidhof, one of the authors of the research, confirmed that what happened in the competition influenced the development of the bird that we eat today.

“The American dream was to have a chicken in every pot, for everyone to be happy. that was the reason [to develop the chicken]”, said the doctor in Animal Science.

“It was with this competition in the 1940s that the first broilers or manufactured chickens, so to speak, were generated,” Professor Thomas tells BBC Mundo.

Now this animal, says Zuidhof, reaches the “ideal” period to be slaughtered in 4 either 5 weeks compared to four months before the contest.

The table shows the results of an investigation of the impact of genetic selection on broiler size.  The study was conducted by professors at the University of Alberta, Canada and published by Elsevier magazine.

BBC World
The table shows the results of an investigation of the impact of genetic selection on broiler size. The study was conducted by professors at the University of Alberta, Canada and published by Elsevier magazine.

And its price, according to an article in the publication The Economistfell by 47% from 1960 to 2019.

Currently, the price of chicken in the US is US$1.92 per pound (half a kilo), while 59 years earlier it was worth the equivalent of US$3.63 (adjusted for inflation).

The contest, along with industrial production methods and subsequent technological development, helped to transform this meat into an accessible product for hundreds of millions of people.

In search of “superior” meat

A documentary produced in 1948, used as publicity for the Chicken of Tomorrow Contest and that summarizes the contest step by step, highlighted that the “ideal” chicken should be one with a large percentage of breast meat and “chubby” thighs.

A chicken with superior white meat characteristics“, the famous actor Lowell Thomas, who served as announcer, is heard saying.

To motivate farmers and chicken breeders, the A & P company, the largest US retailer at the time, offered US$10,000 as a prize for the winners of the contest.

The competition, which was organized by a committee led by the US Department of Agriculture, began first at the state level.

Several chickens hang from a rope while being inspected at the Chicken of Tomorrow Contest

North Carolina State University

On the one hand, the jury would evaluate the characteristics of the animal, such as its uniformity and size, texture and feathers. On the other, how cheap it was to produce.

Competitors had to breed their best broilers to meet the criteria required by the committee to create the “bird of tomorrow.”

Between 1946 and 1947 there were 68 state competitions. That last year there were five regional competitions, from which 40 winners from 25 US states were chosen to compete at the national level.


The finals began in March 1948. Cars and trains loaded with 720 eggs for each of the finalists traveled from coast to coast to Maryland, where they were cared for in a controlled environment until they hatched.

Once hatched, the chicks were identified with a number and sent to a hatchery at the Delaware Agricultural Experimental Extension.

Broiler chicken production.  [  9.220 millones Fue la cantidad de pollos de engorde producidos en EE.UU. en 2020.  ] Source: US Department of Agriculture, Image: A broiler chicken on a farm

There they were fed while their weight, health and appearance were constantly monitored. After 12 weeks the animals were sacrificed.

On the day of the award ceremony, the birds were presented as if they were “ready for sale”, with their skin plucked, distributed in large boxes in a large room.

The Arbor Acres breed of chicken, bred by Connecticut businessman Henry Saglio, came in second. While Charles and Kenneth Vantress, from California, won first prize with a cross between a Red Cornish and a New Hampshire Red.

They were chosen as winners because of the efficient way their bodies processed food, as well as their economy of production.

As an artistic spectacle, a float decorated with flowers was paraded, while a young woman with a crown flanked by US flags waved and smiled.

She was called the “queen of the broiler”.

Genetic selection and industrial production

The contest to encourage farmers and breeders to continue improving chicken breeds was held for another three years. The Vantress rose again as winners in the new cycle.

According to an article published in the journal National Geographic and written by the journalist Maryn McKenna who has investigated the US poultry industry for years, by 1960 the bird improved by these entrepreneurs was the genetic “father” of 60% of the country’s broilers.

But the process of “developing” the “chicken of tomorrow” did not stop there.

Warehouses in which chickens are raised at an industrial level

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In the sheds where chickens are raised industrially, there can be tens of thousands of these animals at the same time for each growth phase.

“There has been more and more genetic selection for these broilers to produce more body mass at an earlier age and to be slaughtered faster,” says Thomas.

Zuidhof, for his part, explains that advances in computational and statistical science allow for better genetic decisions.

However, this is not the only factor that relates to broiler body growth.

In the equation it is also necessary to take into account their life cycle and the way in which they are raised, an issue that in some people arouses criticism.

Birds, continues the professor, live for less time than other species and this influences their growth faster.

Image of thousands of chickens in a chicken raising shed

Getty Images

“Trait growth rate, yield and efficiency are highly heritable. And since we get a lot of chickens each year, the progress of genetic selection is really fast,” she says.

In 2020, some 9.22 billion broilers were produced in the US alone, according to a report from the US Department of Agriculture.

Broilers are usually raised on huge farms where tens of thousands of birds stay for the approximately 40 days of growth.

They consume high-protein foods, such as corn and soy, for about 23 hours a day thanks to a light system that interrupts their sleep cycle.

The space where they live is not cleaned until they are slaughtered and a new litter of birds arrives, since there can be 20,000 to 50,000 in a single shed. They remain on their waste in the meantime.

Thomas, the expert in animal archaeology, says that outside of this controlled environment the birds do not survive. They are genetically predisposed to rely on farm technology.

Hundreds of chickens in the shed of an industrial production farm

Getty Images
Experts affirm that the industrial raising of chickens is harmful to the animal. Due to genetic alterations, they suffer diseases such as heart disorders or locomotion problems. Although the companies claim that they have improved their care methods.

“The reality is that in the form of production there is nothing normal for these animals,” he says. “The ethical problems are huge. You are growing another living thing just to kill it, for your own consumption.

For his part, Walter Suárez-Sánchez, a veterinarian and doctor in animal behavior, argues that poultry production has harmful effects on the animal.

This NGO consultant Mercy for the Animals indicates that birds often suffer from locomotion problems and joint pain caused by their weight, as well as heart failure and other metabolic diseases.

The feces on which they live create skin and feather problems.

But Zuidhof has another perspective.

“Few farmers get up in the morning and say, ‘I’m going to make life miserable for chickens today.’ They all want their birds to be okay,” he maintains.

“Farmers thrive when their birds are doing well, when production is good. There is a great correlation between the health of the birds and their performance capacity, so that is a motivation,” he adds in a conversation with BBC Mundo from his laboratory in Canada.

Does it have an impact on health?

The genetic crosses that allow the rapid growth of the chicken and, consequently, industrial production, do not have a direct impact on the health of the human being, explained the experts consulted by BBC Mundo.

chicken breasts in a supermarket

Getty Images

“It’s all based on science, nothing scary,” says Zuidhof, debunking the common comment that broilers are given growth hormones.

However, Suárez-Sánchez stressed that the possible threats to public health generated by raising animals at an industrial level have been verified, such as some viral and bacterial diseases that are generated by the unhygienic conditions of some farms.

“They promote certain pathologies capable of jumping from one animal to another and potentially affecting humans,” says the veterinarian. Some examples are salmonella, e-coli, and certain types of flu.

To prevent outbreaks, farmers and breeders sometimes give chickens antibiotics. This technique could also represent a problem for human health, due to the resistance that bacteria create to drugs.

“Bacteria not only reach humans through animals, but also remain in the environment, where they can also present traits of resistance to antibiotics,” he maintains.

A chicken breast cooked and served on a plate

Getty Images

In recent times, Zuidhof adds, some governments have passed policies to reduce the intake of antibiotics in broilers, such as in the European Union, which prohibits the use of human reserve antibiotics in veterinary medicine.

Scientists are also working on new genetic crosses to develop hens that not only grow faster and have more meat, but are resistant to disease.

But for Suárez-Sánchez, the solution to protect animal welfare and public health is to make the transition to the production of proteins from other organisms.

A contrarian option

On the outskirts of Miami, on a small open-air farm, Guillermo Guerra distributes grain to his broilers.

Guillermo Guerra's farm on the outskirts of Miami.  Chickens are seen grazing

Ronald Avila-Claudio
According to Guillermo Guerra, he decided to raise his chickens outdoors because it is a “more dignified” way of producing meat, protecting animal welfare.

The animals scratch the earth, dig, the wind moves their feathers. They are surrounded by a chain link fence, and have several wooden sheds where the caretaker places the food.

Since 2019, the Colombian raises the birds on grass, in an alternative far from the big industries. He believes that his way of producing meat is much more dignified for the animal.

On his farm, the chickens take about 90 days to grow, as they follow their normal sleep cycle and eat fewer hours each day. If anyone gets sick, he says, they are separated from the rest.

“In an industrial factory none of this is going to happen, that is the big difference. We believe that the animal, raised in this way, can develop naturally“, says the owner of Nourished Pastures.

Guillermo Guerra, poultry farmer

Ronald Avila-Claudio
Guillermo Guerra started raising chickens in Miami for his own profit. He now has a farm and sells the birds direct to the consumer. They are raised on pasture, outdoors.

Guillermo was a vegetarian, he disagrees with the way of producing animal protein on a large scale. His little business started precisely with the intention of having his own chicken.

But the people around him began to take an interest in meat. Now he raises and sells about 90 birds per growth cycle. His job is almost to swim against the current.

After Chicken of Tomorrow Contest chicken breeders, farms, and meat processors became a huge industry with international reach.

By 2020, according to the US Department of Agriculture, the value of broiler chickens produced was $21.7 billion, well above other birds such as turkey, whose production was worth $5.19 billion.

Mackenna states in his brief for National Geographic that the contest enabled breeders such as Peterson, Vantress, Cobb, Hubbard, Pilch and Arbor Acres to become major brands in the chicken breeding market.

Shed on the Guillermo Guerra farm where chickens are raised on pasture

Ronald Avila-Claudio

According to the author of the book Big Chickenthe complexity of the family trees these firms created then ensured that the birds could not breed outside of their businesses.

The original companies that today make up Cobb-Vantress and Aviagen, two major broiler genetic selection multinationals, participated in the Chicken of Tomorrow Contest.

On its website, Aviagen states that it distributes breeder chickens in more than 100 countries. Under his umbrella are four broiler brands.

Cobb-Vantress, which claims to be the oldest chicken farming company, founded in 1916, has factories in seven countries, with a presence on basically every continent except Africa.

Chickens graze outdoors on a Miami chicken farm

Ronald Avila Claudio

“The winners of the contests Chicken of Tomorrow they did more than create new birds; when they transformed chickens, they also recreated the poultry industry,” says Mackenna in the magazine.

The Miami breeder, meanwhile, sells his meat direct to the consumer. He must do it at a price three times more expensive than in the common market.

Most consumers, Professor Thomas points out, “cannot afford to buy the most expensive”.