Pig Farming Key welfare issues

There are many welfare issued raised by the farming of pigs, but the confinement of breeding sows is the most controversial. There are two stages to the housing of breeding sows:

• The confinement of sows in individual sow stalls for all or part of the period between conception and farrowing (birth of the piglets).
• The confinement of sows in individual farrowing crates from around 1 week before and 3-4 weeks after farrowing

Pig gestation (the period between conception and farrowing) is just under 4 months and piglets are weaned at 3-4 weeks. As soon as the piglets are weaned the sow is made pregnant again. Breeding sows tend to have around 8 litters over a 4-year period. From the age of 8-10 months each breeding sow is generally either pregnant or lactating and for much of the following 3 years she will be confined in either a sow stall or a farrowing crate.

What is a sow stall?

A sow stall is a metal-barred stall that houses a single sow or gilt (gilts are young female pigs that have not yet produced a litter of piglets). Sow stalls are installed in long rows within a shed with an access way between each row. The floor of the stall is usually concrete with a slatted covered trench for drainage at the rear. A standard sow stall is just 2 m long and 60 cm wide. The sow cannot turn around in the stall and can only take a short step forward or back. When the sow lies down her legs protrude into the neighbouring stall.

The gestation period for pigs is just under 4 months (almost 16 weeks). The current model code allows for the continuous use of sow stalls over the entire period of a sow’s pregnancy. Around 26% of sows in Australia are kept in stalls for the full duration of every pregnancy. Most other farms singly house their sows for the first few weeks and then group-house until farrowing (62% of sows are housed this way). A small number of producers use extensive systems, such as group housing in paddocks or in large semi-outdoor shelters.

Sow stalls were originally introduced to enable individual monitoring of sows, reduce feeding competition and bullying, and to house pigs at high stocking densities. However, pigs are very social animals and individual housing prevents them from interacting naturally, resulting in high levels of stereotypical behaviour (repeating the same action over and over again) and unresolved aggression. Movement is severely restricted in sow stalls and there is no means of exercise, leading over time to reduced muscle development and bone strength, and difficulty standing up and lying down.

The pig industry argues that sow stalls are necessary in the first 6 weeks of pregnancy to avoid aggression between sows resulting in injury and increased rates of miscarriage. However, animal welfare groups argue that pregnant sows can be held successfully in groups provided that they are properly managed, have sufficient space and the ability to avoid aggressive encounters, such as through the use of get-away areas or partitions.

What is a farrowing crate?

In intensive systems, a few days before giving birth the sow is moved into a farrowing crate. A traditional farrowing crate confines the sow inside a metal-barred pen that measures 2 m by 50 cm. The bars of the pen are designed to prevent the sow from crushing her piglets but they also prevent the sow from moving or turning around. The sow is confined in the crate from 1-2 weeks before giving birth until the piglets are weaned, usually at 3-4 weeks of age. The farrowing crate is different from a sow stall in that it is slightly narrower and has an area around it where the piglets can move away from the sow.

Farrowing crates have been designed to maximise the survival of piglets, but this is at a cost to the welfare of the sow. RSPCA Australia advocates that housing systems for farrowing sows must be designed to safeguard the welfare of both the piglets and the sow. Sows should not be held in farrowing crates for any longer than is necessary to ensure that the piglets have been successfully weaned.

Traditional farrowing crates do not provide nesting or bedding for the sow. Pregnant sows are highly motivated to seek a sheltered nesting site and collect material for a nest. These behaviours are severely frustrated in traditional farrowing crates.

Farrowing pens may allow for a suitable compromise. There are a number of experimental designs that have adapted the traditional farrowing crate to provide bedding and more flexibility and movement for the sow, while maintaining a high level of protection for the piglets. There are also extensive systems in use where farrowing takes place in individual huts with bedding, where the sow is free to move around and go in and out of the hut.