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Understanding modern poultry breeding

Modern hybrid breeding techniques have transformed contemporary chickens and turkeys into the most genetically modified animals on the planet. How did it happen and what does it mean for farmers and for our health?

The end of traditional breeding

In the not-too-distant past farmers needed healthy animals to turn the greatest profit. Most breeding was accomplished by carefully selecting healthy males and females of any particular chicken or turkey breed and allowing them to mate. The resulting offspring would possess, more or less, the same characteristics as the parent birds. Breeding lines that were hardy and that worked well economically became what we now know as “standard-bred,” sometimes called “heritage.”

Heritage birds come from named breed lines with birds that mate naturally, grow at a reasonable pace, and live long, vigorous lives outdoors. True heritage breeds existed prior to World War II—just before hybrid genetics took off.

The rise of feed supplements, highly controlled confinement systems, and the subtherapeutic use of antibiotics and other antimicrobials misaligned welfare concerns with profitability. Today, the dominant hybrid breeding techniques select for profitability at the expense of welfare.1 This has produced billions of sick, immunocompromised birds that have transformed the global poultry industry into what Farm Forward Board Member and writer, Jonathan Safran Foer, has called “the Silicon Valley of viral development.”

The rise of hybrid breeding

A relatively recent technique in animal agriculture, hybrid breeding depends on a different logic and method than traditional breeding.2 It involves a complicated process of crossbreeding (breeding genetically dissimilar birds), requiring producers to maintain multiple specialty “breeder” lines—often animals that previously would have been considered mutants. These inbred lines carry specifically identified genetic mutations causing, for example, fast growth, larger egg clutches, or obesity, and are not the birds we typically eat. The different lines are then crossbred in pre-determined sequences—often ten to twenty crosses3 —to produce the eggs that then become the hybrid meat birds (“broilers”) or hens that lay the eggs we do eat (“layers”).

Unlike traditional breeding, hybrid breeding techniques ignore the overall health of the parent birds in order to preserve a particular “desirable” genetic mutation, like fast growth. Many of these breeder bird lines have especially severe welfare problems. This is unsurprising given the narrow purpose they serve as carriers of a genetic trait. For example, chronic hunger is endemic in lines that are essential for today’s fast-growing meat birds.4 This means that these birds are physiologically incapable of ever feeling satisfied, condemned to live in the agitated state of an animal desperately trying to fill its stomach. By genetically preventing birds from experiencing satiety, producers ensure that the birds will keep eating, thereby gaining weight more quickly. The cost in terms of welfare is difficult to calculate, amounting to a new form of genetic violence.

Unfortunately, the “end” birds that consumers eat also often inherit many of the problems bred into the parent stock. The result is a very different, less healthy animal than the traditionally bred chicken or turkey. Recently, with greater demand from concerned consumers and increased awareness of the issues surrounding factory farming, long overdue reforms to factory farm welfare standards have begun. Improving things like the physical space given to animals on factory farms, however, is only one component of higher welfare poultry production. Birds with typical hybrid genetics cannot live full, comfortable lives even in higher welfare conditions.5

Good for corporations, bad for farmers

Industry reliance on hybrid birds puts control in the hands of the companies that breed the birds rather than with the farmers who raise them. This is especially worrying because today a mere three companies—Cobb-Vantress, Hubbard, and Ross—control 80% of all chicken genetics.6 These are the companies that provide genetics for familiar brand names in poultry like Tyson, Pilgrim’s Pride, Sanderson, Perdue, and Koch.

Because hybrid birds either simply cannot reproduce on their own or create offspring that do not share their parents’ desired traits, farmers have no choice but to return to factory hatcheries for each new flock.7 By contrast, one flock of standard-bred, heritage birds can serve a farmer for life, producing physically robust offspring generation after generation. Heritage birds thrive in pasture settings, where they are hardy enough to forage, withstand the elements, and resist most naturally occurring pathogens.

More fat, less protein

Beyond the welfare costs, intensive breeding of hybrid birds has profoundly altered the biological makeup of birds. Today’s fast-growing hybrid chickens provide more calories from fat than from protein.8

How should we respond?

To improve welfare in the poultry industry and reverse the nutritional decline of the birds, we must do two things. First, we must ensure that poultry farms provide higher welfare living conditions (abundant pasture, places to nest, perches, etc.) for their birds. Additionally, we must eliminate hybrid genetics that cause animals to grow too big too quickly or lay too many eggs, in favor of animals bred in accordance with Dr. Bernard Rollin’s Principle of Conservation of Welfare: newer breeds should have at least the same level of welfare as previous breeds.9 Until industry takes these steps, Farm Forward calls upon people to divest from this corrupt industry by refusing to buy its products.

The rise of hybrid birds in the poultry industry has been a hidden source of cruelty with profound consequences for public health, including antibiotic resistance and new pandemics. Farm Forward is dedicated to informing consumers about the realities of the poultry industry, and we hope you’ll join us in working toward more humane, sustainable, and just alternatives to factory farming.



For one useful discussion see, Cindy Skrzycki. “Old Rules on Poultry Categories May Fly the Coop,” The Washington Post, 7 Oct. 2003.


O.A. Hanke (Ed.) (1974). American Poultry History, 1823-1973, American Poultry Historical Society: Layayette, IN.


Frank Reese Jr., personal communication, June 28, 2012.


Farm Forward is working to determine a more precise definition of “fast-growing.” Most industry chickens grow to market weight in 5 or 6 weeks. Commonly used standard-bred, heritage chicken breeds grow to market weight in 16-18 weeks. We know that 6 weeks is far too fast and we know that at 16 weeks is a long-established healthy growth rate. We also know that birds that grow to market weight in 8 to 9 weeks are healthier and have fewer welfare problems than those that are raised in 5 or 6 weeks and that birds that go to market in 10 to 12 weeks do better still. What we don’t know precisely is if there are birds that can grow to market rate in faster than 16 weeks while maintaining optimal health and welfare for both broiler birds and the parent stock. Some advocates argue that birds that go to market in 10 to 12 weeks can achieve optimal welfare, but the results are far from conclusive and others vigorously disagree with this conclusion. It may well be that the thousands of years of breed refinement that created chickens that reach market weight in 16 to 18 weeks has already pushed the animals as far as possible while retaining robust health. Farm Forward sees the welfare concerns of fast-growing birds to be among the most pressing issues in farmed animal welfare today.


J.A. Mench & P.B. Siegel (1997). “Poultry,” Animal Welfare Compendium, USDA.


A. Fanatico, S. Polson, and H. Born (2005). Poultry genetics for pastured production. ATTRA, The National Sustainable Agriculture Information Service. Accessed 11 Jun., 2012.


Y. Wang et al. (2009). Modern Organic and Broiler Chickens Sold for Human Consumption Provide More Energy from Fat Than Protein. Public Health Nutrition 13(3).


Read more about Conservation of Welfare here.