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The lifecycle of farmed pigs

Pigs are smart, sociable and inquisitive animals. Today’s pigs descend from wild boars that were domesticated approximately 10,000 years ago in various locations in Asia and then crossed with wild boars in Europe. A pig’s natural lifespan may be up to 20 years, however in commercial pork production pigs can be slaughtered as young as 6 months.


Breeding herds

The breeding animals in a pig herd include the boars (entire male pigs), gilts (young female pigs that have not yet given birth) and gestating (pregnant) sows. Mating of pigs may occur via natural or artificial insemination. Breeding herds are most commonly housed in indoor systems with or without outdoor access, or entirely outdoor systems. In indoor systems, boars are housed individually and gestating gilts/sows may be housed in individual stalls or group pens. In outdoor systems, gilts and sows are kept in paddocks, and boars may be kept separate or housed with the gilts/sows.


Most pigs in Australia are housed in conventional indoor systems. In conventional systems for the first five days after mating gilts/sows are usually confined in sow stalls (or gestation stalls) before being returned to their group housing. The Australian pig industry has committed to voluntarily phasing out sow stalls after the first 5 days following mating (where the sow is confined to a mating stall) in favour of group housing for pregnant sows. It is estimated that around 80% of sows in Australia are now group housed during their pregnancy. Unlike sows in other countries which can be confined in sow stalls for the entirety of their pregnancy.

In outdoor systems, at mating gilts/sows are brought into larger mating pens for natural mating or artificially inseminated after which they are then released back into a pen or paddock.


Towards the end of pregnancy, sows in a conventional farming systems are moved into farrowing crates to give birth.

The farrowing section of a piggery houses sows due to farrow (give birth) as well as sows with piglets up to the point of weaning. The farrowing crate separates the sow from her piglets but allows piglets access to the sow’s teats so that they can drink. A sow may be confined in a farrowing crate for up to 4 weeks. Whereas, in extensive outdoor systems, pregnant sows are moved to farrowing huts that are located in a smaller outdoor area or paddock. In a farrowing hut the sow is not separated from her piglets and is able to build a nest prior to giving birth as bedding is often provided.

Both sow stalls and farrowing crates confined pigs so that they cannot turn around and can only take a short step forwards or backwards. When confined like this pigs are unable to perform highly motivated behaviours such as nesting at farrowing or foraging. To read more about the animal welfare issues associated with sow stalls and farrowing crates, click here.

In the first few days of life, piglets undergo several husbandry procedures such as teeth clipping, tail docking and ear notching. To read more about the animal welfare issues associated with these husbandry procedures, click here.

Some piggeries that operate exclusively as breeder farms, only house breeding animals. Any progeny (their piglets) born are removed from the piggery at, or just after, weaning and sent to farms where they grow out.


Piglets after weaning can be housed in indoor, semi-outdoor or outdoor (free range) systems.

In conventional indoor systems, piglets after weaning are moved into group pens and moved between different sheds depending on the stage of production. Piglets in semi-outdoor system are moved into large sheds/barns with bedding such as straw or rice hulls, that may also have access to an outdoor pen area. While in outdoor free-range systems, piglets are kept outdoors in paddocks with access to shelter with bedding. To read more about some of the animal welfare issues associated with pig farming, click here.

Weaned piglets are raised for 5-6 months after which they are transported to an abattoir for slaughter.



When pigs reach market weight they are transported on trucks from the farm to an abattoir for slaughter. Market weight may vary from 45kg to 110kg (at around 6 months old).


Pigs are most commonly slaughtered using either gas (carbon dioxide) or electrical stunning systems. Electrical stunning systems are more commonly used in smaller abattoirs as they require individual handling and restraint of pigs. Whereas, gas stunning systems are used in larger abattoirs and allow for group stunning. To read more about the welfare advantages and disadvantages of these stunning systems, click here. Once unconscious, pigs are then bled out to cause death prior to regaining consciousness.

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Updated on March 17, 2020
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