Battery hens live in highly automated, windowless sheds containing up to 100,000 hens; they are cramped in long rows of stacked "battery cages."  Up to 10 hens may inhabit an area of 2.33 ft sq.  That is less than half the size of a sheet of A4 (8.5x11) paper per hen; they have a wingspan of 30-32 inches.  Battery cages have sloping wire floors that prevent a hen from sitting, sometimes causing a hen's feet to grow around the bars leaving her immobile and starving to death.  Battery cages have wire walls in which hens often get their head stuck, leading to a slow death of starvation. 

Male chicks, who are of no value to the egg industry, are immediately killed.  They are either tossed into garbage bags, left to suffocate or to be crushed, or are macerated in high-speed grinders.   For the female chicks, after birth they are kept in grow out buildings for about 20 weeks.  They are often kept in dark except at feeding times.

Battery hens are housed in flocks up to 1,000 times their natural size, battery hens are unable to establish a social hierarchy normal to free flocks.  The size and nature of the cages prevents hens from spreading or stretching their wings.  They are prevented the basic natural instincts of perching, scratching, roosting, dust-bathing, and nesting quietly.  They are thus caused to become aggressive and attack other hens.

A hen may be immobilized by having her toes grow around the floor or by catching her head or wing in the bars of her cages.  Unable to access food or water she will die.  Instead of allowing hens material to scratch their toes on to prevent overgrowth some farmers remedy the situation by simplying clipping the hens' toes.

According to Dr. Lesley J. Rogers, in The Development of Brain and Behavior in the Chicken, "In no way can these living conditions meet the demands of a complex nervous system designed to form a multitude of memories and make complex decisions" (Dr. Lesley J. Rogers, The Development of Brain and Behavior in the Chicken, cited in Davis, Karen, Prisoned Chickens, Poisoned Eggs, Summertown, TN: Book Publishing Company, 1996, p. 51).

Battery hens suffer from feather-loss, blisters, tumors, foot and leg deformities (they choose more natural floors over wire-mesh even if have always been kept on wire), osteoporosis (eggshells come from the bones, and the bones became weaker and weaker as they make more and more eggs), Fatty Liver Syndrome, Swollen Head Syndrome, heat stress, mash, mold toxins, mouth ulcers and many other diseases.  Veterinary care is non-existent, as individual hens are considered cheap and expendable.  Critically ill birds are thrown onto "dead piles."

To reduce cannibalism among frustrated hens, laying hens are often "debeaked" as chicks:
 

"It didn't take poultry produces long to figure out that control over light meant control over productionÖ  Egg producers try to create the illusion of eternal spring by keeping the lights on a little longer each day.  After about a year of this, the flock's productivity drops, and many producers use 'force molting' to revive it" (Animal Factories, p. 50).   The egg industry molts hens by starving them for up to 3 weeks.  During the forced molt, mortality doubles each week.  This process shocks the hens into another laying cycle.  Force-molting has also been linked to higher rates of Salmonella.  The practice has been banned in Great Britain since 1987. 

Battery hens are fed hormones and antibiotics; they are prone to bacterial infections and exposed to pesticides.  "The egg industry adds antioxidants to chicken feed to lengthen hens' laying cycles.  These chemicals inhibit the formation of peroxides during the birds' metabolic activities, which can damage and age hens' egg-producing calls and tissues.  Poultry producers use arsenical compounds to speed growth, raise feed efficiency, and boost egg production" (Animal Factories, p. 68).  "Some egg producers use power sprayers that roll along the aisles shooting mists of insecticides up through the cage floors onto the birds" (Animal Factories, p. 66).

"Life is so hard in the cages of the automated layer house that 25 percent of the hens put in the cages die or are'ëculled' during an average eighteen-month laying cycle" (Animal Factories, p. 110).

"Losses from disease and stress run high in the caged layer house.  Some producers told us with pride that the 'cull rate' - the percentage dead and dying birds removed from the cages each day - was quite low, that it ran between 1 and 1.5 percent each month.  That seemed quite low until we realized it added up to a loss of 12 to 18 percent of the original flock by the end of the first year in the cages.  In most cases, layer hens are kept in the cages for eighteen to twenty months or more.  The cull rate generally increases as the birds age, but let's assume that it remains constant at 1.25 per month.  We find that the egg industry is accustomed to losing about one-quarter of its birds by the time their short egg-productive lives are over" (Animal Factories, p. 25).

"Under natural conditions chickens can live as long as fifteen to twenty years; in the modern egg factory, however, hens last only about a year and a half." (Animal Factories, p. 6).

In 1888 the average hen laid 100 eggs per year; now she lays 257.  "Layer hens of the 1930s produced an average of 121 eggs a year.  Through genetics, today's hens nearly double that figure.  But apparently this is not productive enough, for poultry scientists keep trying to develop a 'superchicken' that will lay an egg a day" (Animal Factories, p. 43).

According to industry magazine, Feedstuff, "At higher egg process, crowding always results in greater profits." (Robert H. Brown , "Toe-Clipping May Help Hens, Improve Returns in Crowded Cages" Feedstuff, May 27, 1985, cited in Animal Factories, p. 161).

The study "Effect of Density on Caged Layers" claimed that a higher degree of crowding in cages, even though it pushed up mortality, produced better profits if the price of eggs was above a given point, meaning: when eggs are expensive hens are cheap.  This simple economic fact gives the lie to claims that since animals in factory farms are productive, they must live happy contented lives.  Even if it were true that putting on weight is a sign of well-being - which it is not - productivity of individual animals is not what counts in factory farm economics.  As the studies above illustrate, individual animals' well-being and productivity can suffer as long as more dozens of eggs can be squeezed from a factory building" (Animal Factories, p. 55).

A hen's body may collapse from the exhaustion of frequent laying, or the hens in a shed may be determined to be "spent."  Spent hens have no commercial value because their flesh is poor and their fragile bones break into the flesh during processing. These hens travel thousands of miles to slaughter, often to Canada, or are disposed of at the farm.  Both transport and slaughter of laying hens is unregulated by the USDA, that hens suffer during transport through extreme weather conditions.  "Imagine the suffering of chickens being trucked from, say, an egg farm in Arizona through the Arizona desert, 'where temperatures even at midnight in the summer are over 100 degrees outside, double that inside,' to slaughter in California, at least an eight to nine hour trip" (Prisoned Chickens Poisoned Eggs, p. 110).

Hens are not electrically stunned prior to slaughtering as, "It is claimed that electrical stunning would inure a financial cost through carcass damage and rejection because of easily fractured bones.  Others have pointed out that while it is true that electrical stunning of hens causes broken bones (on average two per bird), during the remained of the processing they acquire and additional four broken bones per bird reflecting rough handling, inhumane housing, and the processing technology itself" (Prisoned Chickens Poisoned Eggs, p. 120).

There are many other instances of cruelty involved with factory egg farming.  "During the winter of 1988-89, heavy snows hit the Ozark region of OK, MO, and northern AK crushing hundreds of poultry sheds and killing an estimated four million birds.  Nearly every summer now we see news account of the deaths of millions of chickens and turkeys across the country as power failures stop the ventilating fans and birds mother, trapped in their own body heat" (Animal Factories, p. 33).   Truck accidents and tornadoes also lead to mass death.