How does the design of the farrowing unit affect the productivity of a sow herd

12 May 2023

Article Farrowing management

In any sow herd, the design of the farrowing unit is an essential issue for economic and productive success. It includes many factors ranging from the number of places, the size of the rooms, the size of the sites, the crates, the floor, the heating, the ventilation, etc.

This article will explain the different types of farrowing units and farrowing crates.

In any sow herd, the design of the farrowing unit is an essential issue for economic and productive success. It includes many factors ranging from the number of places, the size of the rooms, the size of the sites, the crates, the floor, the heating, the ventilation, etc.

This article will explain the different types of farrowing units and farrowing crates.

The farrowing unit

The farrowing unit is one of the most critical parts of a herd, mainly because it is the most expensive building.

It must be designed considering that it should provide comfort for the sow and the newborn piglets (one of the essential items are the temperature requirements) and accommodate the staff during management procedures.

Types of farrowing crates

Most of the sows are housed in crates approximately five days before farrowing and until the weaning of the piglets, at around 28 days of age. The primary purpose of the farrowing crate (first introduced in the 1960s) was to reduce the risk of the sow crushing her piglets.

The confinement of animals in cages receives significant criticism from public opinion, and the industry is moving towards innovative housing for farrowing sows.

There are different types of farrowing crates depending on the sow's confinement level, and each kind has its advantages and disadvantages.

Conventional types of farrowing crates

Conventional farrowing crates are economical, efficient, and safe, maximizing piglet survival as the primary objective. However, they pose welfare problems for the sows and piglets.

Within the classic farrowing cages, you can bet on crates with:

  • Fingers: it is vital to bear in mind that they can take away a piglet's space, and this, in litters as numerous as the current ones, should be avoided.
  • Protective bar: it can completely cover the upper row of breasts. This can be overcome with a mobile protective bar; the height of the bar is adapted to the sow and thus avoid covering part of the udder.

Another critical part of the design of classic farrowing crates is the addition of an anti-crush internal swing bar. It is essential to prevent the sow from lying down suddenly, crushing her piglets.

As we said, the main disadvantage of this type of farrowing crate is welfare problems. There is:

  • A restriction of movement: the sow cannot turn around.
  • An absence of the possibility of building the nest: nesting behavior makes the sow feel calmer and more relaxed during farrowing, but to do so, she needs space and manipulative material.
  • An inhibition of maternal behavior. This generates stress in the sow that can lead to an increased risk of stillbirths and welfare problems in the piglets due to the increased risk of redirected aggression from the sow toward the piglets.

shutterstock_1241096011Conventional farrowing crates are economical, efficient, and safe.

Temporary confinement farrowing crates

The sow can turn around, but movement can be temporarily restricted during the hours around farrowing.

Individual "zero confinement" farrowing crates

The sow is housed individually and is not caged at any time. Single farrowing pens resemble conventional farrowing crates but without the box and with some facility features to protect the piglets. Designed pens are more elaborated and larger, allowing the sow to separate the defecation and resting areas. In addition, they provide a design that facilitates the change of posture of the sow.

Kinane et al. (2022) concluded that "zero confinement" farrowing crates can:

  • Benefit sow welfare: improved tear stain scores suggested that sow stress levels may be reduced in this system compared with conventional farrowing crates.
  • Improve sow locomotory health due to the increased freedom of movement throughout lactation.

The main disadvantage of this kind of crate is the vulnerability of neonate piglets. As the sow can move more freely, it risks crushing her piglets if her movements are not delicate, so the piglets must be well protected. The sow is exhausted during farrowing and is still in pain for several hours after farrowing.

Farrowing Crate and litter performance

Depending on the type of farrowing crate, productive parameters such as piglet growth and neonatal mortality can be affected, as we have already mentioned when talking about the advantages and disadvantages of each of them.


Piglet mortality is one of the top concerns of farmers and veterinarians. During lactation, there are a lot of causes that increase piglet mortality in the farrowing unit, but the most important is crushing.

Hales et al. (2015) conducted a study to determine the effect of confinement from day 114 of gestation and the first four lactation days on farrowing progress and piglet survival. They concluded that confinement did not affect farrowing progress, but reduced piglet mortality compared to loose-housed sows.

Moreover, Yun et al. (2019) determined that immediate postnatal piglet mortality, mainly due to crushing, may be associated with potential increases in the frequency of postural changes, duration of standing, and incidence of trapping in the open crate system.

On the other hand, Nicolaisen et al. (2019) attributed piglet crushing that occurred during the first three days after birth to piglet behavior because the first 72 h postpartum was characterized by sow inactivity. But they also concluded that temporary confinement after birth could be a practical compromise for sows' and piglets' welfare.


Among the multiple infectious causes of pre-weaning piglet mortality, scours (caused by viruses, bacteria, parasites, or a combination) are the most significant.

But there are also aspects related to the facilities that can be the origin of disease in piglets that causes an impact on litter performance.

One of these aspects is the floor. Zoric et al. (2008) observed that the most severe abrasions at carpus and soles were seen in the system with a new solid concrete floor and a slatted floor over the dunging area. Moreover, they concluded that peat provides a soft and good bed for piglets.

Types of farrowing units

Scientific articles published about free farrowing systems are becoming more frequent every day. However, the practical implementation of these systems can raise doubts and concerns, especially relevant in areas with a hot climate where heat stress can be a problem.

Conventional farrowing unit with crates

As we said, the crate is designed to restrain the sow to limit her posture changes and movements. But, for welfare reasons, other systems were designed to allow the sow greater freedom of movement within the existing footprint of a conventional crate space.

In this kind of farrowing unit, a question to address is: should the sows be housed facing the wall or the corridor?

With a sow facing the wall and back corridor, it is easier to control the farrowing, and, in case of need for assistance, it will work more comfortably and safely and is easier to clean. On the contrary, to access the feeder, we must enter each time in the farrowing area, with the consequent increase in time and risk of disease transmission.

One solution to that issue is using a double corridor, which increases construction costs.

What will determine that decision is the feeding system we use. If it is automatic, we could place sows facing the wall without needing a front corridor. On the other hand, in more manual systems, a double passage is necessary to access the feeder easily.

Farrowing unit with pens

Baxter et al. (2012) described this type of farrowing unit as follows: "These systems include a range of modified designs in which the crate is absent."

This design could be:

  • Simple: a larger, solid-floored, straw-based system.
  • Elaborate: designed pens with defined regions, including separate dunging and lying areas and additional pen 'furniture' such as rails or sloped walls to assist sow posture changes and protect piglets.


The practical implementation of free farrowing systems can raise doubts and concerns.


Group farrowing unit

These systems allow sows and litters to mix before weaning. Most of them are based on multi-suckling accommodations. Both sows and piglets have more space and are often housed on straw.

Sows are initially housed in individual pens and are herded together with their litters on days 10-21 post-farrowing. Alternatively, sows can be grouped before farrowing giving access to separate farrowing areas that can be removed later.

Some common concerns about group and free farrowing are:

  • Risk of crushing.
  • Management of aggressive sows, little maternal sows, or very active sows.
  • Manage heat stress.
  • Type of floor.
  • Hygiene of pens and sows.
  • Manipulable material.
  • Control of the feeding system.
  • Governance of difficulties around farrowing and the need for extra time for it.
  • Staff security.

Farrowing unit conditions

A well-prepared farrowing unit is critical to the farm's success, but the task is often overlooked or considered less important than other daily tasks. To achieve this, we must:

  • Clean all surfaces.
  • Disinfect to remove pathogens.
  • Inspect in detail the farrowing unit.
  • Pay attention to the safety of the piglets.
  • Set an adequate temperature in the farrowing unit.

Moreover, the farrowing unit management includes tail docking, teeth clipping, castration, administering iron and coccidiostats, etcetera.

But these managements will only be effective if the farrowing unit conditions are adequate.

For example, in the case of group farrowing units, Zhang et al. (2020) concluded that extra care in management needs to be taken to avoid piglet loss (adding nest material will enrich the behavior of sows and piglets).

Cross-fostering is routinely performed on most commercial swine herds. But it must be taken into account that increased freedom farrowing units may also facilitate undesirable sow responsiveness towards cross-fostered piglets, including piglet-directed aggression. King et al. (2020) suggested that foster sows and litters experience increased disruption after cross-fostering in loose lactation systems; however, piglet performance is comparable to crate-housed piglets. Moreover, piglets exhibited reduced average daily gain after cross-fostering.


The importance of the design of maternity wards both at a productive and economic level for the future development of a farm implies the need to analyze it calmly before building a farm. In this analysis, an important part is to weigh the pros and cons of the farrowing unit and the farrowing crate.





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Baxter, E.M.; Lawrence, A.B. & Edwards, S.A., (2012). Alternative farrowing accommodation: welfare and economic aspects of existing farrowing and lactation systems for pigs. Animal 6(1), 96-117.

Ceva, (2022). Farrowing Unit Management.

Ceva, (2022). How to Reduce Piglet Mortality in the Farrowing Unit.

Cheon, S.N.; Jeong, S.H.; Yoo, Z.Y.; Lim, S.J.; Kim, C.H.; Jang, G.L. & Jeon J.H., (2022). Effect of alternative farrowing pens with temporary crating on the performance of lactating sows and their litters. Journal of Animal Science and Technology 64(3), 574-587.

Free farrowing.

Glencorse, D.; Plush, K.; Hazel, S.; D’Souza, D. & Hebart, M., (2019). Impact of Non-Confinement Accommodation on Farrowing Performance: A Systematic Review and Meta-Analysis of Farrowing Crates Versus Pens. Animals 9, 957.

Goumon, S.; Illmann, G.; Moustsen, V.A.; Baxter, E.M. & Edwards S.A., (2022). Review of Temporary Crating of Farrowing and Lactating Sows. Frontiers in veterinary science, 9, 811810. Doi: 10.3389/fvets.2022.811810

Hales, J.; Moustsen, V.A.; Nielsen, M.B.F. & Hansen, C.F., (2014). Higher preweaning mortality in free farrowing pens compared with farrowing crates in three commercial pig farms. Animal 8(1), 113-120.

Hales, J.; Moustsen, V.A.; Devreese, A.M.; Nielsen, M.B.F. & Hansen, C.F., (2015). Comparable farrowing progress in confined and loose housed hyper-prolific sows. Livestock Science 171, 64-72.

Kinane, O.; Butler, F. & O’Driscoll, K., (2022). Freedom to move: free lactation pens improve sow welfare. Animals 12(14), 538. Doi: 10.3390/ani12141762

King, R.L.; Baxter, E.M.; Matheson, S.M. & Edwards, S.A., (2019). Consistency is key: interactions of current and previous farrowing systems on litter size and piglet mortality. Animal 13(1), 180-188.

King, R.L.; Matheson, S.M.; Baxter, E.M. & Edwards, S.A., (2020). Sow behavior and piglet weight gain after late cross-fostering in farrowing crates and pens. Animal 14(9), 1923-1933.

Lange, A.; Hahne, M.; Lambertz, C.; Gauly, M.; Wendt, M.; Janssen, H. & Traulsen, I., (2021). Effects of Different Housing Systems during Suckling and Rearing Period on Skin and Tail Lesions, Tail Losses and Performance of Growing and Finishing Pigs. Animals 11(8), 2184. Doi: 10.3390/ani11082184

Nicolaisen, T.; Lühken, E.; Volkmann, N.; Rohn, K.; Kemper, N. & Fels, M., (2019). The Effect of Sows’ and Piglets’ Behavior on Piglet Crushing Patterns in Two Different Farrowing Pen Systems. Animals 9, 538.

Pedersen, L.J.; Berg, P.; Jørgensen, G. & Andersen, I.L., (2011). Neonatal piglet traits of importance for survival in crates and indoor pens. Journal of Animal Science 89(4), 1207–1218.

Pig333, (2010). Dimension and design of the farrowing unit.

Verdon, M.; Morrison, R.S. & Rault, J.-L., (2019). Group lactation from 7 or 14 days of age reduces piglet aggression at weaning compared to farrowing crate housing. Animal 13(10), 2327-2335.

Vissing Agro. Farrowing units.

Zhang, X.; Li, C.; Hao, Y. & Gu, X., (2020). Effects of Different Farrowing Environments on the Behavior of Sows and Piglets. Animals 10, 320.

Zoric, M.; Nilsson, E.; Mattsson, S.; Lundeheim, N. & Wallgren, P., (2008). Abrasions and lameness in piglets born in different farrowing systems with different types of floor. Acta Vet Scand 50, 37.

Yun, J.; Han, T.; Björkman, S.; Nystén, M.; Hasan, S.; Valros, A.; Oliviero, C.; Kim Y. & Peltoniemi, O., (2019). Factors affecting piglet mortality during the first 24 h after the onset of parturition in large litters: effects of farrowing housing on behavior of postpartum sows. Animal 13(5), 1045-1053.

Valid recommendations and rules according to EU regulation should be followed.

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