A farrowing house is a specialized building on a pig farm where sows give birth and nurse their piglets during the first weeks of life. It’s designed to keep newborn piglets alive and warm while giving the sow a controlled space to deliver and lactate. In commercial pork production, the farrowing house is one of the most carefully engineered buildings on the farm because the birth and nursing period is when piglets are most vulnerable.
What Happens Inside a Farrowing House
The farrowing house covers three distinct phases: nest building (the sow’s natural pre-birth behavior), birth itself, and lactation, which typically lasts three to four weeks before piglets are weaned. Each phase places different demands on the facility, and the building has to balance the needs of a 300-plus-pound sow with those of piglets that weigh roughly two to three pounds at birth.
Most farrowing houses contain rows of individual pens or crates arranged in a long, climate-controlled room. Sows are moved in shortly before their expected due date and remain until their litter is weaned. Once every animal leaves the room, the entire space is cleaned and disinfected before the next group arrives. This all-in, all-out approach dramatically reduces disease transmission between groups.
Farrowing Crates and Pen Layouts
The most recognizable feature of a conventional farrowing house is the farrowing crate: a metal frame roughly 2.2 meters long and 0.6 meters wide that holds the sow in place and prevents her from turning around. The crate sits inside a larger pen, typically 3.5 to 4.5 square meters total, which gives piglets room to move around their mother while staying protected.
The crate exists primarily to reduce crushing deaths. Newborn piglets cluster near the sow for warmth and milk, and a sow lying down can easily trap a piglet beneath her. Research comparing crates to open pens found that the risk of piglet death was 14% lower in crated systems, with crushing deaths specifically increasing by 6 to 9% in open, confinement-free pens. The original goal when farrowing crates were introduced was to keep pre-weaning mortality below 10%.
Within each pen, piglets have access to a “creep area,” a designated corner or strip along the side where only the small piglets can fit. This area usually has a solid floor (sometimes heated) and a heat lamp overhead, giving piglets a warm retreat away from the sow’s body.
Solving the Temperature Problem
One of the trickiest engineering challenges in a farrowing house is that sows and piglets need drastically different temperatures. A lactating sow is comfortable at around 19°C (66°F). Newborn piglets need air temperatures between 32°C and 35°C (90°F to 95°F), nearly double what the sow prefers. If you heat the whole room for the piglets, the sow overheats, eats less, and produces less milk. If you cool it for the sow, the piglets chill and become susceptible to disease.
The solution is creating microclimates. Heat lamps or heated floor mats in the creep area keep piglets warm, while the room itself stays at a temperature closer to the sow’s comfort zone. This two-zone approach means the piglets learn quickly to shuttle between the sow for nursing and their heated area for resting.
Flooring and Waste Management
Farrowing house floors use a combination of materials chosen specifically for each zone. Under the sow, cast iron slats provide durable, cool footing with good traction that minimizes teat and foot injuries. The coolness of the iron actually works as a feature: it’s comfortable for the sow but uncomfortable enough for piglets that they’re less likely to linger beneath her, reducing crushing risk.
In the piglet creep area, polypropylene plastic slats replace the cast iron. Plastic doesn’t conduct heat away from the piglets’ bodies the way metal does, so they experience less chilling. This reduces rates of scours (diarrhea) and other cold-stress diseases. The two flooring types interlock to create a nearly flat surface.
Beneath the slats sits a manure pit. Waste drops through gaps in the flooring, with some designs featuring 50% openings in the creep area for efficient manure filtration. This keeps the living surface cleaner and drier without requiring constant manual removal of waste.
Ventilation and Air Quality
Farrowing houses rely on mechanical ventilation to manage humidity, ammonia, dust, and temperature simultaneously. A typical setup uses wall-mounted fans and pit fans beneath the floor. In winter, wall fans may shut off entirely while pit fans continue running at lower rates to conserve heat while still exhausting ammonia from the manure pit below.
Ammonia is the primary air quality concern. It builds up from waste in the pit, and the rate at which pit air mixes with room air directly controls ammonia concentrations. In one winter study modeled on an Iowa farrowing facility, increasing the pit-air-exchange ratio from 10% to 30% of total ventilation raised ammonia levels by 154%, though both readings remained well below the 7 parts-per-million industry exposure recommendation. Getting this balance right matters for both the animals’ respiratory health and the safety of farm workers spending hours inside.
Feeding and Water Systems
Lactating sows eat significantly more than gestating sows because milk production is energy-intensive. Farrowing pens include individual feed troughs, often served by automated delivery systems that can be programmed to dispense precise rations on a schedule. Some farms use electronic feed weighers and load cells to track exactly how much each sow consumes, since a drop in feed intake can signal health problems.
Water is delivered through nipple drinkers mounted at different heights: one set positioned for the sow, another lower set sized for piglets. Some systems use bowl drinkers or trough floaters instead. Piglets begin exploring water and solid creep feed during the nursing period, preparing them for weaning.
Technology and Monitoring
Modern farrowing houses increasingly use sensors and cameras to monitor the birthing process and piglet welfare. One emerging approach uses sound cameras, devices equipped with arrays of 64 microphones that can pinpoint where a sound originates within a pen and display it as a colored spot on a visual map. These systems can detect the onset of farrowing by picking up pre-birth sounds from the sow, then monitor for piglet distress calls that might indicate a crushing event or a stalled delivery.
Activity meters and standard security cameras with built-in microphones also help farmers keep watch over dozens of sows without being physically present for every birth, which often happens at night. The goal of these tools is early intervention: catching a problem minutes after it starts rather than hours later during a routine barn check.
The Shift Away From Crates
Farrowing crates remain standard in most of the world, but regulatory pressure is building to phase them out. Austria has mandated a transition by 2033, and Germany by 2036. The European Commission has signaled plans to prohibit all cage systems, with possible implementation as early as 2027 following a transition period. New Zealand committed to phasing out farrowing crates by 2025, requiring free-farrowing pens of at least 6.5 square meters total, with 5.0 square meters dedicated to the sow.
Free-farrowing and temporary-crating systems represent the middle ground many farms are exploring. Temporary crating allows confinement for up to 72 hours around birth (the highest-risk window for crushing) and then gives the sow freedom to move for the rest of lactation. These larger pens, ranging from 5 to 8.5 square meters depending on the design, are sized using calculations based on the sow’s body dimensions and the space needed for turning, lying flat, and nursing a full litter. The trade-off is real: producers transitioning to open systems should expect some increase in piglet mortality, particularly from crushing, but the welfare gains for the sow, including the ability to turn around, nest, and move freely, are driving the legislative push worldwide.