Farrowing crates are used primarily to prevent sows from accidentally crushing their piglets during the first weeks of life. Crushing accounts for 20 to 40% of all piglet deaths before weaning, making it one of the top two killers of newborn pigs alongside starvation. The crates restrict the sow’s movement so she can only stand up and lie down in a controlled way, reducing the chance that she rolls onto or steps on her litter. First introduced in the 1960s, farrowing crates remain standard in most commercial pig operations, though they are increasingly controversial.
The Crushing Problem Crates Were Designed to Solve
On intensive farms, 5 to 25% of newborn piglets die before weaning. Starvation and crushing together explain 50 to 80% of those deaths. Sows typically weigh 300 to 500 pounds, and their natural movements during and after birth, particularly rolling from side to side, can be fatal for piglets weighing just a few pounds. Research has attributed 18 to 65% of crushing incidents to the sow’s rolling behavior and general movement, with the wide range depending on crate design, pen environment, and management quality.
A large meta-analysis comparing farrowing crates to open farrowing pens found that piglet mortality was 14% higher in pens where sows could move freely. The number of piglets born alive and the number of stillborns didn’t differ between the two systems, which means the survival gap comes down almost entirely to what happens after birth: live piglets dying from crushing or exposure in the days that follow.
What a Farrowing Crate Looks Like
A farrowing crate is a metal-barred enclosure within a larger pen. The crate itself holds only the sow, while a surrounding “creep area” gives piglets space to nurse, rest under a heat lamp, and move freely. The combined crate and creep area must be at least 3.2 square meters (about 34 square feet), with common pen sizes around 2.1 by 1.7 meters. The sow can stand, lie down, and stretch, but she cannot turn around. Bars on either side keep her positioned so piglets can access both sides of her udder for nursing.
Sows typically enter the crate about four days before their expected farrowing date and remain there through a weaning period of roughly 21 days, for a total stay of about 25 days per litter. After weaning, the crate is cleaned and prepared for the next sow.
Management Benefits Beyond Crushing Prevention
Producers value farrowing crates for more than just reducing piglet deaths from overlaying. The confined setup makes it safer and easier for farm workers to intervene when piglets need help. Assisted suckling, where a worker guides a weak piglet to the udder, is common in the first hours after birth. Cross-fostering, or moving piglets between litters to balance litter sizes, also requires handling newborns near a large sow. Both tasks are significantly more dangerous and difficult when the sow can move freely.
Crates also allow targeted heating. Newborn piglets are extremely vulnerable to cold because they have almost no body fat and can’t regulate their temperature well. Heat lamps or heated mats are placed in the creep area right at the birth site, and the predictable positioning of the sow in a crate makes this setup reliable. In open pens, sows may choose to farrow in different locations, making it harder to ensure piglets are born near a heat source.
The Welfare Cost to the Sow
The tradeoff for piglet safety is significant stress and physical harm to the sow. In the days before giving birth, sows have a strong instinct to build a nest, gathering and arranging materials like straw or branches. This behavior is hormonally driven and deeply ingrained. Crated sows, unable to perform it, show clear signs of frustration: they root at the bare floor, bite the metal bars of the crate, and frequently shift positions. Researchers consider this redirected nesting behavior, essentially the sow attempting to carry out a biological program with no materials and no space.
The stress isn’t just behavioral. Crated sows show elevated cortisol (a stress hormone) and increased heart rates compared to sows given nesting materials and space. Prolonged confinement also changes opioid receptor density in the brain, a marker associated with chronic stress. On the physical side, the repeated effort of lying down and standing in a tight space causes skin damage and limb lesions from contact with the floor and bars. Sows housed in crates had greater difficulty lying down, particularly on the first day, and the sliding and pressure involved produced more frequent leg injuries.
These findings have led researchers to conclude that preventing natural nesting behavior results in measurably impaired welfare, including increased stress, more physical injuries, and disrupted hormonal processes that can affect labor and milk production.
How Alternatives Compare
The main alternative is a farrowing pen, a larger enclosed space where the sow can turn around, walk, and often access nesting materials like straw. Some designs use a “freedom crate” or temporary crating system, where the sow is confined only during and immediately after birth (typically two to seven days) and then released into the larger pen for the rest of lactation.
The evidence on these systems is mixed but increasingly encouraging. The 14% higher piglet mortality rate in open pens is a real and consistent finding, but some of that gap narrows with better pen design and management. When farrowing pens included enrichment materials like straw, stillborn rates in crates were actually 22% higher than in pens, suggesting that nesting material may help sows have smoother deliveries. The number of piglets weaned per litter showed no significant difference between crates and pens in pooled research, though researchers cautioned that study designs varied.
Temporary crating aims to capture the benefits of both approaches: confining the sow during the highest-risk window for crushing, then giving her freedom once piglets are mobile enough to escape her movements. This is where much of the industry’s current research and investment is focused.
Where Crates Are Being Phased Out
Several European countries have already banned or restricted traditional farrowing crates, including Sweden, Switzerland, Norway, Denmark, and Austria. The European Union has signaled broader movement in this direction. In the United States, no federal law addresses farrowing crates, and they remain standard practice on the vast majority of commercial operations.
The economic barrier to change is real but not as steep as many producers assume. One analysis found that converting from crates to group housing added roughly $9 to $10 per finished pig in total costs, driven mainly by the fact that open systems hold fewer sows per square foot and require more labor. Construction costs for new group housing facilities were comparable to, or in some cases lower than, building new crate facilities. A Canadian study found that a group housing facility for 1,000 sows cost 30% less per sow space than conventional crate housing when space allowances were moderate. Hoop barns, a simpler open structure, cost about $570 per sow space compared to $820 for conventional crate buildings.
The conversion cost for existing facilities is relatively modest. Retrofitting a ten-year-old crate facility to group pens added just $1.15 per finished pig. The larger ongoing expense comes from reduced capacity and higher labor needs, not from the physical renovation itself.