Genetic Selection and GMOs in Poultry

It's no secret that the birds you grow today are different than those grown 40 years ago. But why?

Genetic Selection and GMOs in Poultry

Recent Poultry Trends

genetic engineering in chicken

According to a study completed at the University of Alberta, from 1957 to 2005, broiler growth increased by over 400% while feed consumption decreased by nearly 50%. The National Chicken Council reported an 85 day grow out to reach 2.89 pounds of live weight in 1940, compared to a 47 day grow out to reach 6.4 pounds of live weight in 2020. So, what is responsible for this intense difference?

Some might suggest that it’s due to the use of steroids and antibiotics, but my personal favorite is the claim that the poultry grown today are GMOs. Read on to learn why this is NOT true, and the real reason behind the massive improvement in poultry weights.

What are genetically modified organisms? 

genetic selection in chickens

GMO stands for genetically modified organism, a name adopted from popular media in reference to genetically engineered organisms. GMO refers to changes made to the genetic makeup of any living organism using biotechnology. GMOs can range anywhere from trees to fungi. These changes in genetic makeup are extremely targeted, and organisms are typically genetically modified to improve production, human health or hardiness.

For example, the first genetically modified organism was a bacteria strain that produces insulin as a treatment for diabetes. Cotton is an example of one of the genetically modified crops that are common today. GMO food has been developed, like corn that is resistant to bollworms. GMO plants like alfalfa—primarily used to feed cattle—have been genetically modified to be resistant to most herbicides. This allows farmers to protect the crop from weeds, which can reduce production and lower its nutritional quality.

Do genetically modified chickens exist?

Or, any genetically modified animals at all? The reasons for lack of GMO animals range from animal welfare concerns to lack of research. The only genetically modified animal currently approved by the FDA is “AquaAdvantage Salmon,” or Atlantic salmon modified to reach an important growth point more rapidly.


There is no such thing as a genetically modified chicken. Although some chicken feed may be made from GMO crops, the birds themselves are not genetically modified. And although there have been studies with transgenic chickens, no genetically modified chickens are commercially available.

The broilers of today are very simply not genetically modified, but the result of decades of genetic selection, or selective breeding, towards a rapidly growing, heavily muscled, feed efficient animal. This means that at no point have genes from other species been introduced to the chicken genome of the birds in commercial poultry houses.

Again, there are no broiler chickens genetically modified!

Genetic Selection in the Poultry Industry

Genetic selection, which is what is used in the poultry industry, is broadly defined as the breeding of plants or animals in order to selectively develop characteristics in the offspring by selecting parent stock with the desired characteristics. This can mean choosing corn with sturdier stalks to seed the next growing season or breeding a dairy cow with poor feet and legs to a bull with exceptional feet and legs. For chickens, this can mean breeding big birds with other big birds to produce a new generation of even bigger birds.

The Chicken of Tomorrow

chicken of tomorrow 1948 national contest sign

The immense growth that produced modern chickens and thus more chicken meat was kickstarted in 1946. A group of major poultry and egg organizations partnered with a supermarket chain to host the “Chicken of Tomorrow” contest. The goal was to find the largest bird with the most breast meat.

Today, the goals of genetic selection in the poultry industry have shifted. Although bird size and muscle mass are still at the forefront of conversation, things like disease resistance, skin and feather color, bone structure and feed conversion have all entered the mix as well!

The Chicken of Today

Genetic selection happens incredibly rapidly in poultry production due to the short amount of time it takes to establish a new generation. In comparison to cattle, which take 9 months to produce an offspring, chickens only take 21 days to fully incubate and hatch. This has allowed for exponential progress in the last several decades.

Broilers today are able to grow to market weight in 6 to 9 weeks using only 1.79 pounds of feed per pound of body weight. Additionally, average mortality has been reduced to 5.3 percent on average compared to 12 percent in 1940. Genetic selection has also been beneficial for chickens who lay eggs.

Genetic selection is not the only process at work here either. It is important to remember that improvements in veterinary medicine, nutrition and environmental technology all contribute to our ability to grow the “chicken of tomorrow,” today!

Feeding our World through Science

Today's agriculture landscape is built almost entirely around the idea of farmers, ranchers and growers producing enough food to provide for the rest of us. Genetic modification and genetic selection are simply mechanisms used to help achieve that goal. Although these practices have drawn negative attention to the agriculture industry in recent years, they have allowed us to reduce the amount of feed needed to grow a bird to market weight, cut the time needed to grow that bird in half and improve mortality across a grow out by nearly 7 percent.

To the researchers, breeders and farmers who contributed to these advances, thank you for your dedication to building an efficient industry capable of providing the world with its favorite lean protein. For those of us who do not fit into the one of those categories, next time you’re eating your Bojangles breakfast biscuit, Chick-fil-A nugget meal or your favorite Zalad, remember that genetic selection and your local poultry grower made that possible.   

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About The Author

Izy Dobbins

Isabella (Izy) Dobbins

This was written by Isabella (Izy) Dobbins, Southland Organics' Marketing Manager. Izy has devoted her education and career to communicating science-related topics. With an enthusiasm for sharing accurate and honest content relating to science and agriculture, she ensures Southland Organics' publications are as informative as they are interesting. Izy graduated from the University of Georgia with a bachelor's degree in advertising, minors in both Spanish and environmental health science and a Certificate in Sustainability. She has been working at Southland Organics since 2021.

Learn more about Izy Dobbins

Erin Flowers

Copywriter and Editor

This was edited by Erin Flowers. As a writer and editor, Erin keeps a close eye on the details. Erin thoroughly researches each topic, fact checking and source searching to give our readers helpful resources for raising chickens, homesteading, and growing lawns and gardens. Erin graduated from the University of Georgia with a bachelor's degree in advertising. She began working with Southland Organics in 2018.

Learn more about Erin Flowers

Erin Flowers
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