will stay in a gestation crate for the four-month period of her pregnancy. Animal welfare advocates regard the use of gestation crates as one of the most inhumane features of intensive
animal production. A 1997 report of the Scientific Veterinary Committee of the European Union, noted that because "overall welfare appears to be better when sows are not confined throughout gestation, sows should preferably be kept in groups."
Aggression Pork producers argue that gestation crates are needed because sows that are housed together in pens will fight; however, reduced aggression can also be achieved with larger pens that kept the animals separate, but allowed them more freedom of movement. There are also other ways of reducing, but not eliminating, aggression besides gestation crates. These include eliminating overcrowding, not mixing pigs from different litters, providing straw or other bedding material, and providing sufficient food that not only meets nutritional needs but satisfies pigs' appetites. Other important means to reduce aggression among sows rely on alternative feeding methods, as many sows will compete with each other for food. These include trickle feeding systems, individual feeding stalls, and electronic sow feeding equipment, all of which resolve feed competition among pigs.
Stress and mental well-being The Washington Post reported in 2001 that researchers have not found sows in gestation crates to have elevated levels of
stress hormones. The paper notes that this suggests their overall health is not compromised. Many studies have shown that sows in crates exhibit behavior such as bar-biting, sham chewing, head weaving, and tongue rolling, indicating chronic frustration and boredom. The
Post writes that a report by veterinarians for the
European Union concluded that abnormal behavior in sows "develop[s] when the animal is severely or chronically frustrated. Hence their development indicates that the animal is having difficulty in coping and its welfare is poor." Sows confined to gestation crates also show behavior that indicates
learned helplessness, such as remaining passive when poked or when a bucket of water is thrown over them. A review by the Scientific Veterinary Council of the
European Commission states that repetitive "
stereotypical" behavior has been found in "every detailed study" of pigs in gestation crates, but not in any other housing systems examined. Some studies have shown that "sow behavior has been shown to differ among housing systems; often it seems to be the non-housing component (i.e., direction of bar, other substances present) of the system that is responsible for the behavior displayed by the sow."
Injuries and physical disease Stereotypic behavior such as bar-biting can lead to physical trauma, such as sores from frequent contact with the metal bars, and mouth sores from sham-chewing and bar-biting. Many other health related issues are to be found among pigs confined within gestation crates as opposed to group housing systems. Some of these include urinary tract infections, respiratory disease, skin lesions (e.g. pressure sores), excessive heat-loss, muscle health, foot injuries, damage to joints, and even lameness. while one study found that crated sows had two thirds the bone density of non-crated sows, with researchers concluding that weakened bones led to a higher incidence of broken bones or injuries Sows can suffer shoulder sores and abrasions to their skin from rocks, sharp edges, and bolts fastening the crates in place. This same flooring is thought to contribute to toe lesions, According to John Webster, head of the Veterinary School at
Bristol University in the United Kingdom, "Sows on concrete in confinement stalls suffer abuse according to all the
Five Freedoms." These include freedom from hunger, discomfort, pain, distress, and freedom to express normal behavior. Sows that have to lay on concrete flooring can experience excessive heat loss and chronic physical discomfort,
Natural behavior In a symposium held in 2002 on swine housing and well-being, Edmond A. Pajor, Associate Professor at
Purdue University, told the audience that "In gestation stalls, sows are prevented from performing many of the behavior patterns that pigs would perform in more natural or less restricted conditions resulting in a negative impact on sow welfare."
Hygiene When given the choice, pigs will relieve themselves far away from where they sleep and eat. Sows in crates are forced to lie, or sit, in or directly above their own fecesanother reason some think there is a higher incidence of respiratory disease among sows confined in gestation crates. == Alternative configurations ==