What are the animal welfare issues with sow stalls?

In Australia, most pigs are housed in intensive indoor systems. In these intensive systems, pigs may be confined and raised in barren environments, which leads to a higher risk of pigs experiencing poor welfare outcomes. Of particular concern are issues associated with the confinement of sows in sow stalls where they are unable to perform innate and motivated behaviours such as foraging, rooting, or interacting socially with other pigs. The RSPCA opposes housing systems that confine pigs for any extended period, including the use of sow stalls and farrowing crates.

What is a sow stall?

A sow stall, also known as a gestation stall, is a metal-barred crate that houses a single female breeding pig for part of her 16‑week gestation (pregnancy). A female breeding pig may be either a gilt (a young female breeder pig who has not yet given birth to a litter of piglets) or a sow (a female breeder pig who has given birth to at least one litter of piglets)¹. A standard sow stall is only 2m long and 60cm wide. While in the sow stall, the sow can stand up and take a step forward or backwards, but she is unable to turn around. The floor of the stall is usually concrete, with a slat-covered trench to catch urine and faeces at the back.

Animal welfare issues with sow stalls

Pigs are intelligent and social animals, with a complex range of behaviours and needs. When confined to a sow stall, sows are unable to perform natural and motivated behaviours, such as foraging, or interacting socially with other pigs. As a result, confined sows can show higher incidences of aggressive behaviours and abnormal behaviours, such as stereotypies (e.g., repetitive bar biting or head swaying) ​[1]​. These behaviours can indicate poor animal welfare outcomes because they are considered to occur when pigs are attempting to cope in an inappropriate environment ​[2, 3]​. Confinement also causes sows’ muscles and bones to weaken, leading to sows having difficulty standing up or lying down due to lack of exercise ​[1]​.

Key animal welfare concerns​ [4]​

movement restriction:

• sows can take only a small step forward or back and cannot turn around
• sows are unable to walk or run
• sows have trouble getting up and lying down
• sows will lie down more often and for longer as well as changing lying position more often due to discomfort
• sows’ increased lying time can result in lameness and foot injuries due to limited fitness and feet getting caught in the floor slats.

inability to perform exploratory or foraging behaviour:

• sows are unable to express innate exploratory, foraging, rooting, and sniffing behaviours
• sows are likely to redirect oral behaviour (e.g., nosing, licking, biting) towards stall fixtures, floor or trough and these behaviours can develop into stereotypies.

stress:

• sows are unable to engage in normal social interactions which leads to stress in a species that is innately social and generally lives in groups
• sows ready for mating are very active and motivated to have social contact which is restricted in a stall
• sows are prevented from establishing a dominance hierarchy resulting in intense aggression between neighbouring sows, in contrast to group housing where it can be resolved and escape from aggression is possible
• sow proximity and visual contact means gilts or younger sows feel intimidated because they can’t hide or move away from perceived threats such as older sows in a neighbouring stall.

insufficient rest/sleep:

• sows are restricted in their ability to get up, lie down and adopt a comfortable lying posture which likely disrupts the amount and quality of sleep
• sows are often in contact with the crate’s metal bars when lying on their side (lateral lying is more comfortable for pigs) resulting in discomfort, tiredness and/or frustration
• sows on uncomfortable (concrete) flooring with lack of bedding suffer from sustained pressure on bony parts of the limbs and development of pressure sores
• sows cannot rest properly on wet and dirty flooring.

hunger:

• sows are motivated to forage for food but are placed on a restricted diet which means they are hungry most of the time
• sows who are hungry are even more motivated to forage for food, however foraging behaviour is impossible in a sow stall.

What are the available alternatives to sow stalls?

The Australian pig industry committed to voluntarily phasing out sow stalls after the first five days following mating (where the sow is confined to a mating stall) in favour of group housing for pregnant sows by 2017. To date, it is estimated that around 80% of pregnant sows in Australia are housed in groups. Where sow stalls are still in place, regulation requires that they not be used for more than six weeks during gestation.

What is RSPCA’s position on sow stalls?

The RSPCA is opposed to the use of sow stalls because of the restrictions and adverse effects that these housing systems have on the movement, social interactions, and behaviour of sows. The RSPCA supports the Australian pig industry’s voluntary phase out of sow stalls to housing systems where sows are housed in groups. Sows can be successfully housed in groups, provided they are properly managed and have sufficient space and environmental enrichment. The Australian pig industry should aim to phase out all remaining sow stalls in favour of group housing systems for gestating sows.

The RSPCA is also opposed to the use of farrowing crates because of the restrictions and adverse effects that they have on the movement, social interactions, and behaviour of sows. For more information on the animal welfare issues with farrowing crates, click here.

1. For simplicity, this article uses ‘sow’ to refer to any female breeding pig.