Transitioning to alternative farrowing systems

Any substantial change brings challenges. Find out how to switch to free or other alternative farrowing systems while meeting the needs of the sow, piglets and stockperson.

Back to: Alternative and free farrowing options for pig farms

What is free farrowing?

Firstly, we need to define some terms:

Free farrowing systems: where sows are non-confined during farrowing and lactation.

Conventional farrowing crate: where sows are confined throughout farrowing and lactation.

Temporary crating: systems where the sow is generally first confined for farrowing and the following few days but is later unrestrained for most of lactation. One slightly different system allows the sow to be unrestrained first during farrowing but can be crated later after farrowing if necessary.

Alternative farrowing systems: where farrowing takes place in any pen or crate that is not of a conventional farrowing crate design or size. This encompasses both free farrowing and temporary crating systems.

All farrowing systems should be designed to meet the requirements (health, safety, behaviour and welfare) of the sow, piglets and stockperson.

Workshop papers: Freedom in farrowing and lactation 2021 – overcoming barriers, facilitating change

Temporary crating

In temporary crating, such as the 360° Freedom Farrower®, sows are restrained for the first few days of parturition (seven days from the birth of the piglets) to protect the piglets while at their most vulnerable.

After those first days, the restraining elements of the crate move away from the sow to allow her free movement now the piglets are safe. The restraining elements can temporarily restrain the sows when handling piglets for vaccination and other husbandry tasks to maintain staff safety.

Some assurance schemes will not allow confinement of the sow at any point, e.g. RSPCA Assured.

Zero confinement systems

In zero confinement systems such as PigSAFE, there is no confinement at any point. Instead, the design of the sow’s lying and living area, as well as clear areas of escape for piglets, are carefully designed. The use of sloping walls, temperature differentials and different flooring zones can all support successful farrowing by allowing natural behaviours to drive sow and piglet to make optimal use of the space.

There are examples of true loose housing systems, i.e. without an individual pen. These systems use large straw barns with individual farrowing spaces or open pens and feeding stations, but sows can mix freely with other sows and litters.

Outdoor systems

Approximately 40% of British sows are kept outdoors, usually in individual huts/arcs placed within individual farrowing paddocks with straw nesting and bedding materials. As such, at least 40% of UK sows are already in free farrowing systems.

Due to limitations on the availability of suitable land, differences in genetic lines and the logistics of outdoor production, it is highly unlikely that all pork production in the UK would switch to outdoor rearing.

Different sow genetics are used in outdoor production. Sows need to be more docile, have better mothering abilities and be physically hardy to deal with their environment. 

Summary: differences between farrowing systems

When switching from one farrowing system to another, the key to success is sufficient training of stockpeople and clear management protocols.

These protocols must be suited to the specific system in use, but producers must be prepared to refine them to suit individual sites as no two pig buildings are the same.


Conventional crates

Temporary crating

Zero confinement

Group systems

Area per sow and littera

4.3 m2

4.3– 6.0 m2

4.8–7.2 m2

7.2 m2+

Cost per sow place per yearb



£441 – £509


Floor design

Fully slatted floors

Fully slatted floors with nesting materials*

Partially slatted or solid floors**

Partially slatted or fully slatted floors, some solid floors with straw

Key features

Fixed, separate areas for the sow and the piglets

Temporary fixed area for the sow that opens up, creep box/area for piglets inaccessible to the sow

Distinct spaces for sow to facilitate nesting and piglets for safety and socialisation

Individual open pens for farrowing and then a group enclosure for sows and piglets to mix freely

Supply of materials (all animals must receive enrichment as described in the welfare codes)

Provision of manipulable materials in line with recommendations in the welfare codes

Nesting materials to be provided to the sow

Nesting materials to be provided to the sow

Nesting materials to be provided to the sow

Duration of confinement

In line with welfare codes minimum 28 days (up to 35 days in 5 week systems)

First seven days of lactation

Zero confinement

Zero confinement

Pros for sows

Provides minimum requirements as described in the welfare codes

Allows expression of nest-building behaviour pre farrowing and increased ability to move during lactation

Allows expression of nest-building behaviour pre farrowing and free movement throughout farrowing and lactation

Allows expression of nest-building behaviour pre farrowing and free movement throughout farrowing and lactation.

In well-managed sows, increases the social interactions of sows

Cons for sows

Conventional crates restrict sow movement for the entirety of farrowing and lactation (about 28 days)

Still a limitation on freedom of movement for seven days

Depending on design can limit the socialisation of sows

Exposes sows to inter sow aggression and risk of injury

Pros for piglets

Highest level of protection from crush injuries, lowering piglet mortality

Protection from crush injuries and reduced mortality during first seven days post farrowing

Design plus good management, when used in conjunction, offer protection against crush injury for piglets

Increased socialisation of piglets with future pen mates

Cons for piglets

Limited social interaction with future pen mates


Limited social interaction with future pen mates. Without appropriate management, a slight increase in piglet mortality

Without appropriate management, an increase in piglet mortality

Higher mortality compared with individual farrowing pen systems due to increased numbers of crush injuries and deaths. More cases of missed suckling

aAreas given include minimum footprint for conventional crates and min/max range for other crate systems.

bCost per sow place per year based on 20-year lifespan and adapted from research from Cain et al. (2013) and Alternative farrowing options in the swine industry - Pork Information Gateway (

*The use of fully slatted floors and nesting materials like straw often requires the modification of slurry management systems such as using a flushing system. This can increase costs at installation.

**Solid floors make use of straw as a substrate and bedding material. Clear zoning of sleeping and dunging areas with a scrape through means bedding will stay dry and clean while allowing good husbandry.

Considerations when using an alternative farrowing system

Any move to an alternative or free farrowing system must consider:

  • The training of the sow (sows will become accustomed to a specific farrowing environment)
  • Continuity – sows will struggle if they are switched between farrowing systems at each parity (common when producers are ‘trialling’ new crate systems)
  • The ability to train staff in new ways of working
  • The availability of labour on the unit
  • The changes to building infrastructure due to new pen designs and space requirements
  • The assurance schemes currently utilised and/or aimed for
  • The biological needs of sow and piglet as well as the health and safety needs of the stockperson

Retrofitting alternative farrowing systems into existing buildings is often substantially more expensive and complex than installation in new builds. 

If you are looking to invest in new farrowing accommodation, consider whether alternative or free farrowing offers safeguarding over potential changes to UK policy around animal welfare in the future.