Pigs that are housed in sow stalls and farrowing crates have no opportunity to engage in exploratory and foraging behaviour, or to interact socially with other pigs. As a result, they show high levels of stereotypical behaviour (repeating the same action, such as biting the bars of the stall and swaying their heads) and unresolved aggression. Pregnant sows are highly motivated to engage in nesting behaviours, but they are frustrated from carrying out this behaviour in farrowing crates, which do not provide bedding or nesting material.
Several types of pig farming systems are used in Australia:
- indoor intensive systems
- semi-indoor extensive systems
- outdoor, free-range systems.
The use of indoor intensive systems for housing pigs raises the most serious welfare issues. Pig producers use indoor systems for a number of reasons, including climate control, ease of cleaning, use of labour-saving machines, protection from predators and control of the animals. However, close confinement of pigs in indoor systems raises welfare concerns because the lack of freedom and barrenness of the surroundings can lead to stress, injury and abnormal behaviours.
The RSPCA is especially concerned about the welfare issues associated with use of sow stalls and farrowing crates in these systems. Breeding sows may be confined in sow stalls or farrowing crates for most of their adult lives.
A sow stall is a metal-barred crate that houses a single sow for all or part of her 16‑week pregnancy. The floor of the stall is usually concrete, with a slat-covered trench for manure at the rear. A standard sow stall is just 2 metres long and 60 cm wide. This is just enough space for the sow to stand up in — she cannot turn around and can only take a short step forward or back. The Australian pig industry has committed to voluntarily phasing out sow stalls after the first 5 days of pregnancy in favour of group housing for gestating sows. Where sow stalls are still in place, regulation currently requires that they not be used for more than six weeks in any gestation (pregnancy) period.
A farrowing crate is a metal-barred pen that is similar in size to a sow stall but slightly narrower. The sow is moved into the farrowing crate a week before before giving birth and is kept there until the piglets are weaned at about 3–4 weeks of age. The crate has an area around it that the piglets can move into to avoid being crushed by the sow.
Most indoor pig producers currently house pregnant sows in groups until a week prior to farrowing when the sow is moved to a farrowing crate to give birth. After farrowing, the sow may be placed in a mating stall up to five days (for artificial insemination) and then return to group housing. Only a small proportion of pig producers use extensive systems, such as group housing in paddocks or in large semi-outdoor shelters. Sow stalls and farrowing crates are not used in extensive systems; rather, pregnant sows are housed in groups and farrowing sows are housed in huts where they remain until their piglets are weaned.
The pig industry argues that sow stalls are necessary to avoid aggression between sows that can result in injury and miscarriage. Other claims are that sow stalls enable individual monitoring of sows, reduce feeding competition and bullying, and enable high stocking densities. The reason for using farrowing crates is to maximise survival of piglets by preventing them from being crushed by their mother.
Welfare issues associated with the use of sow stalls and farrowing crates arise from the fact that pigs are intelligent, social animals, with a complex range of behaviours and needs. When kept outdoors, they spend many hours every day exploring their environments and foraging. They are able to avoid aggressive behaviours from other pigs by moving away from each other.
Sow stalls and farrowing crates can also cause physical problems for the sows. Because they are unable to exercise, their muscles and bones deteriorate and they may have great difficulty in standing up or lying down.
The RSPCA is opposed to the use of sow stalls because of the restrictions and adverse effects that this housing method has on the movement, social interactions and behaviour of sows. The RSPCA also supports the use of farrowing systems that provide freedom of movement and meet the sows’ and piglets’ behavioural and physiological needs; this includes the use of bedding to allow nesting behaviour. The RSPCA supports the Australian pig industry’s move to phase out the use of sow stalls to a production system where pregnant sows are housed in groups. Sow stalls and farrowing crates are not permitted under the RSPCA Approved Farming Scheme standards for pigs.
Animal welfare groups, including the RSPCA, believe that pregnant sows can be successfully housed in groups, provided that they are properly managed and have sufficient space to avoid aggressive encounters. Alternatives to sow stalls include straw yards with individual or electronic feeders to regulate food intake. There are also alternatives to farrowing crates. These include farrowing pens, which provide bedding and allow more movement, and extensive systems that use individual huts for farrowing.
The Model Code of Practice for the Welfare of Animals: Pigs sets minimum welfare guidelines for people involved in pig farming.
Visit the RSPCA Approved Farming Scheme website for more information.