Group farrowing systems

The range of farrowing systems with reduced or zero confinement includes those with a group lactation element. Find out what this means in practice, including the costs and benefits.

Back to: Alternative and free farrowing options for pig farms

What are group farrowing systems?

In group farrowing systems, sows and piglets are housed in large group pens for most of the lactation period.

Sows and piglets may start in an individual pen and later be moved into a group enclosure. Alternatively, sows may be kept in a group throughout farrowing and lactation, with free access to more private areas from a central space for the duration of farrowing.

Mixing sows and piglets in such systems, before weaning, can reduce post-weaning aggression for sows and weaning stress for piglets, but it can also have a detrimental impact with regard to aggression and crushing.

Limited data regarding group farrowing is available, but studies generally indicate group systems show the most inconsistent results and highest piglet mortality.

As with all systems, sows may be temporarily enclosed at feeding and during management tasks for the welfare of stockpeople. This does not constitute restraint as the sows enter the feeders voluntarily.

Examples of group farrowing systems

  • Deep litter group systems (Ljungstrøm and Thorstensson)
  • Two-stage group systems (Rivalea)
  • Group lactation system

View a list of manufacturers and suppliers of alternative farrowing accommodation

Key features of group farrowing systems

Group farrowing systems occupy a larger footprint than conventional systems as they combine an individual farrowing space for the sow (these may be temporarily confined for up to 72 hours) and a space for group lactation.

Both the Ljungstrøm and Thorstensson type systems use a deep litter system onto which fresh straw is placed to maintain a dry and clear laying area. The group lactation system from Wageningen University uses a partly slatted system more closely resembling conventional sow and piglet accommodation.

Although studies are limited, they show that group housing systems offer the most inconsistent results, often exhibiting high mortality and an increase in the number of missed suckling opportunities for piglets.

Any use of group housing systems needs to assess the whole system the farm is integrated into and question how the sows and piglets can be managed to ensure a high standard of welfare and productivity. 

Producer insights on group farrowing systems

EUPiG received a number of entries of best practice for the challenge ‘loose farrowing’, which can be accessed here and sorting the entries based on challenge: Loose farrowing.

Case study 1 (Italy)

In Italy, the producer wanted to eliminate all farrowing cages and all cages in gestation (note: sow crates have been banned in the UK since 1999).

The producer installed a farrowing space of dimensions 2 x 3 m with the possibility of enclosing the sow for up to three days after farrowing. The piglets have a defined and heated creep within the farrowing space.


  • Installation of the farrowing spaces was made via a retrofit into existing buildings - this resulted in the number of sows at farrowing being reduced by about 17% due to the larger size of the farrowing spaces themselves
  • The costs of making the new farrowing spaces are about 70% higher than conventional farrowing cages and a larger covered space is required due to the sizes of the pens
  • While the number of piglets born per sow is improving significantly, the number of piglets crushed has unfortunately increased:
    • mortality in farrowing pens averages 12% against 8% when using farrowing cages
    • weaning takes place at about 28 days
    • the increase in the number of piglets born per sow compensates the increase of preweaning mortality
  • Costs of labour have significantly increased compared to cage housing for the cleaning of boxes with partially slatted floors - the extra labour time is ½ labour unit per 800 sows and our sow farm increased labour input from 3.5 to 4 labour units

Although there is limited data available, studies generally indicate that group systems show the most inconsistent results and highest piglet mortality and missed sucklings due to cross-sow suckling issues (Baxter, 2017).


  • The producer found that the benefits are closely linked to the increased space for both sows and piglets, with pigs exhibiting a wider range of natural behaviours
  • The free housing of sows improves their psychophysical condition and their productive career
  • There are also economic benefits thanks to a lower replacement rate of sows
  • Weaned piglets per sow remained the same as before (about 10.5, which is lower than the UK average)

The producer felt that the good health conditions of weaned piglets are functional (determinant) to the success of the antibiotic free supply chain. Pigs have a better value for both hams and the quality of their meat. Finisher pigs at the end of the supply chain are paid 15% more. However, there is no proven link between free farrowing and reduced antimicrobial usage.

Case study 2 (Spain)

A Spanish Iberian producer (small-scale, fewer than 200 sows) built a brand new, green field site development to support higher productivity premium production of Iberian pork.

The farm implemented an intermedium stage between individual lactation and weaning called ‘shared lactation’. The farm mixes different litters with their sows in a communal area so that piglets can interact with each other to reduce the post-weaning stress. They have also designed a farrowing crate that can be closed or open.

Sows spend the first three days in the farrowing crate and then it is opened, and they are moved to the communal area. Since the buildings were new, the time and costs associated with retrofitting were not an issue.


The producer feels the main benefits are better animal welfare and a more sustainable farm. Their primary focus is on the concept of ethical and sustainable production.

Points to note

  • The producer has not worked with conventional farrowing crates to compare performance
  • The farm produces with the Iberian breed which normally has fewer piglets born alive compared to conventional farms
  • They are now collecting data to compare their mortality rates to other Iberian pig systems, together with the benefits that they observe of better growth rates and better weaning weight
  • Iberian pigs are sold at a premium price (depending on the type of Iberian, it can be two euros more/kg compared to conventional)
  • Loose farrowing systems may be implemented in other EU countries interested in producing with higher welfare standards
  • The system may also be implemented in other countries, specifically in local breeds aiming at high-quality markets with a public expectation of welfare
  • Production losses may be recoverable because of the added value of producing with higher welfare (but this is a niche market)