Photo: Jo-Anne McArthur / We Animals Media
In 2021, 129 million pigs were slaughtered in the United States. Each of these pigs was born to a mother who likely spent the majority of her pregnancy in a gestation crate, a metal cage so small that she was unable to move apart from sitting, standing, or lying down. This restriction of mother pigs’ movements prevented them from creating nests for their future piglets, led to repetitive behaviors such as chewing or biting, and contributed to injuries such as scrapes and ulcers. Despite these outcomes, gestation crates have remained the dominant housing method for mother pigs within industrialized farming. Some states and countries are slowly moving toward outlawing the use of these cages, but their popularity among farmers remains high.
There are a few different housing options for pregnant pigs on factory farms. Gestation crates are the most common choice. It’s important to note that prior to actually giving birth, the mother pigs—called sows by the industry—are moved to different types of housing, often “farrowing crates,” which are often even more restrictive than gestation crates.
Gestation crates, also called gestation stalls, house individual pregnant pigs and provide just enough space to stand, sit, lie down, and take a step forward or backward. Pigs do not have the freedom even to turn around, let alone or enjoy natural behaviors such as rooting or creating nests. As a result, mother pigs housed in gestation crates are inactive. They obviously spend less time walking than pigs kept in other housing systems, and even spend less time standing.
Alternative forms of housing for pregnant pigs include group pens, free-range, and pasture-raised.
Group pens house multiple pregnant sows together. Though there are several different types of group pens, the most popular ones in the United States are built indoors, with slatted floors so that feces may drop through to a sewage system below. The number of pigs housed in a group pen system varies from five to several hundred. The social life of pigs in group pens needs to be managed, because pigs have a social structure that can lead to an unequal distribution of food if feedings are not carefully performed. The social structure can also lead to injuries due to aggression and fighting within the group.
When housed in a free-range system, pregnant sows are in theory given access to the outdoors. However, the USDA only regulates the term “free range” in regard to poultry. Free-range labels applied to lamb, cow, and pig products are not regulated by the USDA. (In regard to poultry, the USDA definition of “free range” only means that birds are allowed access to open air—which could mean 5 minutes per day of access to a screened-in concrete slab—according to Consumer Reports.) Without additional welfare certifications or regulated claims, products that carry the “free range / free roaming” claim are often meaningless for animal welfare.
Pigs who are raised on pasture—which is what many people envision when they hear the phrase “free range”—face issues like parasites from the outdoors and the potential for exposure to the elements. Pasture-based farrowing is considerably higher welfare than group pens or gestation crates.
Pigs have a very sensitive social structure. When placed into group housing systems pigs are more likely to be injured due to aggressive behavior from the other pregnant pigs. By separating all of the pigs and placing them into individual cages the risk of being injured by other pigs goes away. Producers are also better able to regulate the amount of food provided to each individual animal. However, the cost for the welfare of the mother pig is very high, as she is not able to engage in natural behaviors or even turn around in her cage. Pigs living in gestation crates are constantly stressed and suffer both physically and psychologically.
While both gestation crates and farrowing crates are highly restrictive forms of housing that are specifically for mother pigs, there are key differences between them. During pregnancy, pigs are housed in gestation crates. Once the mother pigs are getting close to giving birth they are then moved out of gestation crates and placed into farrowing crates. Gestation crates have room only for pregnant pigs; farrowing crates immobilize mother pigs but include space that piglets can occupy while accessing their mother’s teats to nurse. Both forms of confinement prevent the mother pigs from moving around and expressing their natural behaviors.
Each gestation crate houses a single pregnant pig in order to keep her isolated from other pigs.
Pigs are placed into gestation crates for the entirety of their gestational period, which is about 16 weeks or 4 months long. This means that for the entirety of this duration the mother pigs are unable to move beyond simply lying, sitting, or standing.
There are several major welfare issues associated with gestation crates, all of which stem from the physical restriction that pigs experience when locked inside. They include the restriction of natural behaviors, the injuries that result from confinement, and the repetitive, purposeless behaviors that mother pigs may develop due to their inability to move. This is not an exhaustive list of the welfare issues with the pig industry as a whole, which are plentiful, but specifically those caused directly by the use of gestation crates.
Pigs are highly intelligent animals who enjoy a wide range of behaviors when in their natural habitats, especially when pregnant. Pigs enjoy rooting and creating nests. When housed in gestation crates, mother pigs are unable to perform these behaviors due to the limitations placed on their movement. Within the cages, pigs are only able to stand, sit, lie down, and perhaps take a step forward or backward.
The length and severity of the confinement that pigs experience in gestation crates can lead to the development of pressure sores, ulcers, and abrasions. The frequency of these injuries is higher in gestation crates than other forms of gestational housing.
For many years we have understood that the behavior of crated sows is comparable to that of humans who are mentally suffering and experiencing severe depression. Despite this, progress on the welfare of pregnant sows has been painfully slow.
Stereotypy or stereotypic behaviors in pigs are behaviors that have no apparent goal or purpose but that are performed repeatedly by animals experiencing intensive confinement. Common stereotypic behaviors include biting, chewing, licking, and rubbing. Such behaviors are frequently seen in mother pigs who are locked into gestation crates. The mother pig is not the only one impacted by these behaviors. Research suggests that the offspring of mother pigs that displayed high levels of stereotypy during pregnancy are different from the offspring of pigs that did not. Specifically, piglets birthed by mothers with lower levels of stereotypy were more vocal, an indicator of excitement. Piglets birthed by mothers that displayed high stereotypy wandered more, which researchers noted could be seen as “explorative” or could result from “increased anxiety.”1
At the federal level, gestation crates are legally allowed to be used when raising pigs for consumption. However, there are several states that have banned gestation crates. The states that have taken this step include Arizona, Colorado, Florida, Maine, Michigan, Ohio, Oregon, and Rhode Island. Two states, California and Massachusetts, have even gone as far as banning the sale of meat that was raised using gestation crates outside of their borders. These states, however, only make up 6.62 percent of the pork production industry in the United States. One of the states with a ban in place, Ohio, is responsible for more than half of that, and its ban does not take effect until 2026.
A handful of countries have passed bans on gestation crates, including Canada, Sweden, and the United Kingdom. The Canadian ban was originally meant to take effect in 2024 but has faced trouble, with industry stakeholders pushing an extension to 2029. Sweden and the United Kingdom were the two first countries to introduce gestation crate bans, with Sweden’s measure being introduced in 1994 and the United Kingdom following suit just a few years later in 1999.
There are two alternatives to gestation crates: group pens and free-range housing. Both alternatives allow mother pigs to move around more than gestation crates, which reduces the amount of stereotypy and injuries due to confinement, and enables the pigs to engage in more natural behaviors.
Group pens can house anywhere from five to a couple of hundred pigs. The primary welfare concerns associated with group pens stem from the social structure that pigs establish. This structure can lead to aggressive behavior and fights. When pigs are housed in group pens it is also important to ensure that all the pigs in the pen are consuming the appropriate amount of food, because if they are not carefully monitored the more dominant pigs are likely to overconsume while the pigs at the bottom of the pecking order are likely to undereat and lose weight.
The housing system that would seem to provide the most freedom and welfare benefits for the pigs is free-range housing or pasture based farrowing. However, the USDA does not regulate the term “free range” as applied to pigs. That means that when it comes to free-range pig products, anything goes. Without additional welfare certifications or regulated claims, labels that carry the “free range claim are often meaningless for animal welfare. Those few farms that allow pigs to farrow on pasture offer the highest welfare conditions for mother pigs.
Mother pigs suffer for months locked in gestation crates and unable to express their natural behaviors or even turn around. Their bodies are treated as commodities by a system of food production that only values them for their ability to give birth. The vast majority of pig products found in grocery stores, including leading retailers like Costco and Trader Joes, come from pigs who’ve been confined in gestation crates. Continuing to support the consumption of bacon, ham, and other pork products means that we are economically propping up the industry that perpetuates these realities. Farm Forward encourages institutions and individuals to divest from industrial pig production. Interested? Learn more about how you can change institutional food policies and change your diet.
Patricia Tatemoto et al., “Stereotypic Behavior in Sows Is Related to Emotionality Changes in the Offspring,” Frontiers in Veterinary Science (March, 2020), https://doi.org/10.3389/fvets.2020.00079.