Fall 2001 Poultry Press Conference Summary
Farmed Animal Well-Being Conference at the University of California-Davis
June 28-29

This conference was sponsored by the Association of Veterinarians for Animal Rights, Animal Place, and United Poultry Concerns. In attendance were animal scientists, producers, veterinary students, and animal advocates. The animals discussed were cattle including “dairy” cows and calves, pigs, fish, and birds. The following is a synopsis of the talks given by poultry welfare specialists Joy Mench and Ian Duncan. Dr. Mench serves on the Animal Welfare Advisory Committees of United Egg Producers and McDonald’s. On May 3, 2000 Dr. Duncan testified before the CA legislature on behalf of Assembly Bill 2141 which would have banned forced molting in California.

Welfare Problems of Laying Hens
Joy Mench, PhD, Director of the Center for
Animal Welfare and Professor of Animal Science,
University of California, Davis

Eight billion broiler chickens and 300 million laying hens are in U.S. agribusiness production each year, with hundreds of thousands, even millions, of birds on a single farm. In this gigantic system individual birds have little value: a whole broiler chicken is worth $4 and the yearly output of [250] eggs per hen amounts to $30. More than 99% of U.S. laying hens are in cages, averaging 8 hens per cage. Hens in cages develop osteoporosis because they get no exercise and because their limited calcium is mobilized for constant eggshell formation instead of for bones.

Space: Average cage space per hen in the U.S. is 48 to 54 square inches. These hens have high stress hormone levels, high mortality, poor feather cover, more fearfulness, and lay fewer eggs than hens with more space. A hen needs 72 square inches merely to stand comfortably. Nor is it just the amount of space but the quality of the space needed by a bird who normally would spend 60% of her day foraging. Hens deprived of nest boxes, dustbathing material, perches, and foraging opportunities suffer. Even noncage “aviaries” in which thousands of hens are confined in a building can produce abnormal behaviors. So-called “cannibalism,” i.e. “tearing the flesh of the other birds,” shows the abnormality of such housing, which is not only too large but too crowded with birds.

Beak Trimming: A blade or laser is used to lop off a third of the top beak and the tip of the bottom beak of laying hens. Beak trimming is definitely a welfare problem. Evidence suggests phantom limb pain, and neuromas [tumors] form in the damaged tissue of the amputated beak stump. Geneticists are working on developing a bird that doesn’t feather peck or “cannibalize” as an alternative to beak trimming.

Forced Molting: The U.S. egg industry molts hens by depriving them of food for 4 to 21 days. Forced molting is not the same as natural molting in which chickens and other birds replace old feathers with new ones each year, usually in the fall. When molting naturally, hens never entirely stop eating and they don’t normally die as a result of good feather maintenance. By contrast, during the forced molt, mortality doubles each week. The egg industry maintains if it does not force molt and reuse surviving hens for the next laying cycle, it will have to hatch nearly twice as many birds as it now does in order to produce new flocks for each new laying cycle. Included will be the hatching of unwanted male chicks to be suffocated or macerated in high-speed grinders at the hatchery. Embryo sexing, which is being studied, could eventually eliminate the hatching of male chicks.

Spent hens: These hens have no commercial value because their flesh is poor and their fragile bones break into the flesh during processing. Spent fowl slaughter plants prefer the “meatier” spent parent flocks of the broiler chicken industry because more money can be made from these birds. Spent hens travel thousands of miles to slaughter, often to Canada, or are disposed of at the farm.

“They have no real value,” explains Canadian Farm Animal Care Trust president Tom Hughes. ‘They are not even worth enough money to go through the normal process of slaughtering and packing. The simplest method of disposal is to pack the birds, alive, into containers, and bulldoze them into the ground. Euphemistically called ‘composting,’ it still amounts to being buried alive. Another method is to pack the birds into the body of the truck. Some 26 million spent hens are imported into Canada from the U.S. each year,’ because disposing of them in Canada is cheaper, ‘and upon arrival, are gassed in the trucks which imported them.’”

–Animal People, May 2000, p. 8


Welfare Problems of Meat-type Chickens
Ian J.H. Duncan, PhD, Professor of Poultry Ethology, Chair
in Animal Welfare, University of Guelph, Ontario, Canada

These chickens, including both the breeding flocks and the [baby] “broiler” chickens derived from them, represent welfare problems on a huge scale. By “welfare,” I mean “what animals feel.” Strong negative feelings—suffering—include pain, frustration, and fear. The biggest modern problem with “meat-type” chickens and turkeys is not infectious disease [which is still rampant] but metabolic.

Heart and Lung Problems: These birds have been genetically selected for fast growing soft muscle tissue. The heart and lungs have a hard time supplying this fast growing soft tissue with oxygenated blood. This can lead to aortic rupture in turkeys, sudden death syndrome (heart attacks) in chickens, and an accumulation of venous blood fluid in the body cavities--ascites syndrome—resulting in suffocation. Ascites is responsible for 5 – 12% mortality in “meat-type” chickens.

Skeletal Problems: The combination of forced rapid growth and excessive weight causes chronic, painful lameness and abnormal gait in “meat-type” birds. The bird’s body grows too fast for the bone plates to accommodate. Consequently the birds develop angular bone deformities, tibiadyschondroplasia, and “kinky back,” in which vertebrae snap and put pressure on the spinal chord, causing paralysis. In breeder turkeys, cartilage gets eaten away at the hip joint because of the overweight. These are not senile turkeys; they are young turkeys. Studies in which lame chickens and turkeys are given painkillers or a choice between food with painkillers versus food without show that these birds are in pain. They choose the painkilling food, and they become more active. Crippled birds suffer also because they may be starving and thirsty and because they cannot avoid aggressive attacks in the crowded sheds.

Ascites and skeletal problems are increasing in “meat-type” chickens and turkeys, which isn’t surprising. While in the 1950s it took 12 weeks to raise a five pound chicken, the time has been reduced to 6 weeks, at enormous cost to the birds. These birds are all extremely unfit. In treadmill experiments, for example, their core body temperature goes up abnormally high. There is also the interaction between their unfitness and their poor environment. The poultry environment is full of dust and ammonia which get into the birds’ lungs. Ammonia destroys the cilia that would otherwise prevent harmful bacteria from being inhaled. As a result, the birds develop respiratory infections such as airsacculitis. They are inhaling harmful bacteria constantly.

“Elective Surgeries” – Mutilations: Male breeder chickens are detoed, beak-trimmed and their combs are dubbed (cut off). Turkeys used for breeding are detoed and beak- trimmed, and the male turkeys’ snoods are cut off (desnooded). All these “elective surgeries” involve pain, perhaps chronic pain. No anaesthetic is ever given to the birds. These mutilations are crude solutions to problems created by modern methods of raising chickens and turkeys. For example, broiler breeder males have been bred, consciously or unconsciously, for hyperaggressiveness. They injure and cause fear in the hens, who cannot escape from these roosters in the breeder houses. Worse, to keep their weight down, “meat-type” breeder chickens are given only 40 – 50% of the amount of food they would normally eat. They are chronically hungry. Their abnormal behavior, such as compulsive pecking, shows they are obviously suffering.

Young birds: A big welfare problem for the chicks and poults (baby turkeys) is that the poultry industry wants “meat-type” birds to start eating immediately. Lights are kept burning in the sheds and the birds are prodded to eat. Consequently, young chickens and turkeys do not get enough rest. By contrast, in nature, hens brood their young periodically throughout the day and continuously through the night to provide both warmth and rest.

Catching, Transportation, and Slaughter. All of these activities are extremely stressful as currently performed. Automated chicken catching machines (“harvesters”) are less stressful than manual catching. Inert gas stunning using, say, argon mixed with nitrogen, would be more humane that the current method of electrically immobilizing the [conscious] birds. Preferably, birds should be stunned in the transport crates, prior to shackling. This would eliminate the stress of being grabbed and shackled while fully conscious as is now the case. It would also be better for the shacklers because there would be less noise, less dust, more light, and better ergonomics.


The next issue of PoultryPress will include a synopsis of the talks by Dr. Lesley Rogers and Dr. Gisela Kaplan, who spoke respectively about “Changing Our Views About the Domestic Chicken” and “ Emotions and Awareness in Birds.”
Fall 2001 Poultry Press NEXT