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25 August 2016
“Broiler Breeder” Chickens: Their Misery Revealed

By Karen Davis, PhD, President of United Poultry Concerns

Chicken investigation video

Watch this new investigation video

Compassion Over Killing’s investigation this summer takes us inside the bleak and brutal world of “broiler breeder” chickens, the hens and roosters who produce the eggs that become the chicks who are slaughtered at 6 weeks old for “chicken.” The investigation was conducted at Tyson Foods facilities in Virginia, but poultry companies, by whatever name, are all “Tyson.”

In Prisoned Chickens, Poisoned Eggs: An Inside Look at the Modern Poultry Industry, I talk about these poor, tortured parent flocks including the “nozbonz” featured in the COK video and an undercover investigation conducted by PETA at the Hudson chicken breeding facility in Maryland, titled, in PETA News, in 1993, “Chicken Hell.”


Treatment of Parent Flocks – “Chicken Hell”

Not surprisingly, many employees vent their frustrations on the birds. A supervisor swore “about a bird who had escaped during unloading and eluded capture, threw a board at her and missed, then kicked her four or five feet into the air. Another shouted obscenities at a chicken he blamed for having made him fall and twist his ankle, then lunged at her, throwing his whole weight on her, and punched her twice. Another, who broke the wing of a bird causing a bone to protrude, blamed the chicken for not letting him catch her.”


Roosters with nozbonz

Parent Flocks: Blackouts and Food Restriction

Chickens raised to produce the eggs that become “broiler” chickens are called broiler breeders. Male and female chicks are raised separately until they are about five months old. At that time, the young hens and roosters are brought together in laying houses that hold from 8,000 to 10,000 birds, with ten or twelve roosters for each one hundred hens. The flock is maintained for breeding purposes for about ten months. At a little over a year old, they are sent to slaughter. Their eggs are gathered and taken away to the mechanical hatcheries; the parents never see their chicks. Throughout the breeding period, roosters are rigorously culled (removed and killed) for infirmity and infertility and because “if a particular male becomes unable to mate, his matching females will not accept another male until he is removed” (Bell and Weaver, 641).

Breeding flocks are kept on floor systems that are part litter (wood shavings) and part wooden or plastic slats. Each adult bird gets two square feet of living space (Bell and Weaver, 821). Breeder houses are equipped with mechanical nest boxes – one for every four hens – and feeders that are similar for the roosters and hens except that “the wires that allow the birds to slip their heads in to reach the feed are closer together on hen feeders than on rooster feeders” (“Growing Up with Tyson”).

The reason for this difference is to keep the roosters from eating the hens’ food as they would otherwise do. Breeding hens and roosters are kept on semi-starvation diets because the characteristics bred into broiler chickens to produce rapid and excessive weight gain in the chicks cause obesity, infertility and mating problems in their parents (Leeson, 49-50).

Left to eat as they please, the roosters become so large, unwieldy and disabled that they cannot mate properly or even move without pain. Even as babies, their legs tremble when they try to stand up and walk a little, like the legs of very old men. To curb these effects, broiler breeder chickens are kept in semi-darkness in “blackout houses” that, added to the ammonia fumes, harm their eyes causing ophthalmic disorders. In addition, as already noted, they are kept on semi-starvation diets designed to control their weight and reduce their food intake (“Chicken-Rage”). Typically, a whole day’s food is withheld from the birds every other day starting at three weeks old or they are fed very small portions in “every-day feeding since it is more efficient” (Leeson, 49). The chickens rush pitifully to the feeders when the food is restored, often injuring their feet and other parts of their bodies in their desperation to eat. Bacteria invade the tissues and bloodstream following these injuries to the skin, particularly the feet, which become inflamed with a painful footpad disease called bumblefoot.

Karen holding a hen on her lap

Karen Davis holds a rescued “broiler breeder” hen blinded by ammonia fumes in a Tyson facility in Maryland. UPC sanctuary photo by Bruce Andrew Peters

“Feed-restricted” chickens gorge themselves when the feeders are refilled, enlarging the capacity of their crop and gizzard to hold even more food, adding to the birds’ frustration. On days when food is withheld, they peck compulsively at spots on the floor, at the air, nonfood objects and each other’s heads, and, if permitted, they drink up to 25 percent more water than normal to compensate for the feeling of emptiness. Because this results in loose droppings and wet ammoniated litter, managers are urged to restrict the availability of water to “birds looking for feed” (Bell and Weaver, 631-633).


Roosters with nozbonz inserted in their nasal cartilage
University of Georgia Photo


In addition to separate feeders for the roosters and hens, many broiler breeder roosters are implanted with a nasal devise called a “nozbonz” to prevent them from poking their heads through the hens’ food restriction grill. Maybe fifty percent of producers in North America use them, according to a University of Georgia researcher in 1999 (Mauldin). They’re used on the Eastern Shore in the U.S. where I’ve seen roosters with the nozbonz fused into their faces, sticking out on either side. The nozbonz is a two-and-a-half-inch plastic stick that is jammed through the bird’s cere (nasal cartilage) when he is five months old. Suzanne Millman, a researcher at the University of Guelph in Ontario, said she “did a few of the birds myself” and found that “it definitely takes quite a bit of pressure to get the Nozbonz through the septum.”

As bad as all this is, Millman writes, “Nozbonz are not effective for the purported objective.” Since the roosters are “extremely food motivated,” they “soon try their own experiments to access the female feeders. Females have a much higher feed allotment than the males due to demands from egg production, so males finish their meals in about 15-20 minutes and females take several hours. Males will turn their heads to get into the grills, and become vulnerable. If attacked by other birds, or frightened, they then often try to pull back and panic. They may injure or even kill themselves. They also sometimes rip the Nozbonz out in the struggle.”

Description: http://www.upc-online.org/fall2002/noz-bonz2.jpg

Photo of Miriam Jones holding rooster with nasal implant by Karen Davis


Abnormally Aggressive Roosters and Hens

A new problem emerged in the poultry industry in the 1990s. An increasing number of reports described broiler breeder males being very aggressive toward females. This is highly unusual because male domestic fowl dominate females passively and seldom show any overt aggression toward them. – Ian Duncan, “Animal Welfare Issues in the Poultry Industry: Is There a Lesson to Be Learned?” 2001, 213.

The “nozbonz” experiment was part of an investigation into the causes of unusual aggression in broiler breeder chickens, a new manmade pathology variously attributed to the birds’ impoverished environment, food frustration, and genetic malfunction (Duncan 1999). In one study, the introduction of “bales of plastic-wrapped wood shavings” to broiler breeder hens was said to “dramatically” reduce their unnaturally aggressive behavior (“chicken-rage”). Studies by Millman and Duncan led them to speculate that attacks by broiler breeder roosters on hens is a genetically-based courtship disorder, since even roosters who have been bred for cockfighting “show little, if any, aggression toward females” (Duncan 2001, 213).


“Courtship Theory” of Rooster Aggression is Rubbish

The courtship theory recurs in Temple Grandin’s book Animals in Translation, which proposes that genetic manipulation of chickens for abnormally fast growth has somehow eliminated the rooster’s courtship dance around the hen that tells her to crouch into a sexually receptive position. When the hen fails to crouch or tries to escape from being mounted by the rooster, according to the theory (which Grandin mistakenly presents as a fact – “She doesn’t crouch down unless she sees the dance. – That’s the way her brain is wired”), the rooster attacks her with his spurs or toes and slashes her to death, an example of what Grandin calls “warped evolution” in animals bred for single traits at the expense of overall fitness (Grandin 2005, 69-72).

The trouble with the courtship theory is that these kinds of hens do crouch, even without a rooster. If you so much as lay your hand gently on their backs or approach them from behind, they will walk or run a little, then stop and crouch abruptly during the spring and summer mating season. In addition, a rooster’s courtship dance around a hen does not automatically cause her to crouch. She may simply curve around and away from the rooster signaling the end of the encounter. She may run away or continue her dustbath or whatever else she was doing when he approached. Her response does not provoke the slashing attack described by observers of broiler breeder chickens in laboratories and commercial breeding operations.

Part of what is wrong with these birds is that they have been artificially bred to become sexually mature at around three months old instead of the normal six months, so that halfway out of their infancy, they have adult sex hormones driving them, without the neurobiological maturity of an adult bird. Add to this the barren environment, eye-impairing darkness and chronic hunger, plus the fact that the broiler-breeder rooster’s body, legs and feet are too big for the hens who are themselves abnormally heavy, disproportioned and slow-moving, and have thin, easily torn skin and nowhere to escape to, and you have predictably abnormal behavior. “Spent” broiler breeder hens whom we’ve adopted into our sanctuary arrive in terrible condition, with large patches of raw bare skin and ragged feathers. Even the soft tuft of feathers that nature designed to hide and protect their ears is missing, exposing the ear hole. This is something you simply don’t see in young adult birds.



After 40 or so weeks of producing fertile eggs plagued by hunger, mutilations, toxic ammonia, fear, pain, stress and disease, broiler breeder chickens are “liquidated” and turned into human animal “food” and nonhuman animal “feed” and pet food products. (North and Bell, 404).

    • Video of “spent broiler breeder” hens and roosters in 1995 truck accident




Bell, Donald D., and William D. Weaver, Jr., eds. 2002. Chicken Meat and Egg Production, 5th ed. Norwell, Mass: Kluwer Academic Publishers.

“Chicken Hell: Research & Investigations Takes You Inside a Hatchery.” 1993. PETA News, Vol. 8, No. 2 (Spring): 10-12.

“Chicken-Rage” (“How to deal with chicken-rage”). 2000. The Economist, 29 April: 79.

Compassion Over Killing. “Tyson Exposed: A Tradition of Torture,” August 2016.

Duncan, Ian J.H. 2001. “Animal Welfare Issues in the Poultry Industry: Is There a Lesson to Be Learned?” Journal of Applied Animal Welfare Science 4.3: 207-221.

Grandin, Temple. 2005. Animals in Translation. New York: Scribner.

“Growing Up With Tyson.” 1991. Tyson Update, June-July: 17-19.

Leeson, Steven. 2007. “Poultry Nutrition & Health: Dietary allowances.” Feedstuffs 2007 Reference Issue & Buyers Guide 78.38, 13 September: 44-53.

Mauldin, Joseph. 1999. “Noz Bonz.” Email to Karen Davis, 24 February.

Millman, Suzanne. 2002. Noz Bonz. Email to pattrice jones, 22 May.



KAREN DAVIS, PhD is the Founder and President of United Poultry Concerns, a nonprofit organization that promotes the compassionate and respectful treatment of domestic fowl including a sanctuary for chickens in Virginia. She is the author of Prisoned Chickens, Poisoned Eggs: An Inside Look at the Modern Poultry Industry, More Than a Meal: The Turkey in History, Myth, Ritual, and Reality, The Holocaust and the Henmaid’s Tale: A Case for Comparing Atrocities, and A Home for Henny, a children’s book. Karen’s Biography


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