Pigs

In much of the world it is common for a pregnant sow to be kept in a sow stall (also called a 'gestation crate') for the whole of her 16-week pregnancy.

A sow stall is a metal cage – usually with a bare concrete/slatted floor – which is so narrow that the sow cannot turn around, and she can only stand up and lie down with difficulty.

Sow stalls deprive pregnant sows of almost all natural behaviours; they cannot explore, exercise, forage or socialise which means they suffer from boredom and frustration.

Sow stalls also increase abnormal behaviour such as sham chewing and bar-biting, indicating severe frustration and stress, and sows in crates can exhibit behaviour likened to clinical depression.

Sow stalls are illegal in the UK, Norway and Sweden and phased out in Germany by 2030, and their use is limited in the EU, with a partial ban enforced from 2013. However, it is still permitted for sows to be kept in sow stalls from weaning of the previous litter until the end of the first 4 weeks of pregnancy.

Several producers are starting to phase out sow stalls voluntarily on animal welfare grounds, due to consumer pressure.

Shortly before she is due to give birth (referred to as ‘farrowing’), a sow is typically moved to a farrowing crate where she will stay until her piglets are weaned (often at only 21 days of age).

The farrowing crate is a narrow metal cage which restricts the sow’s movements and hinders her ability to interact with her piglets. Bars on the side of the crate give the piglets access to the sow’s teats to feed and prevents them from risk of crushing by keeping them away from the sow as she lies down.

Farrowing crates severely restrict the sow’s movement and her strong motivation to build a nest before giving birth. They also prevent the sow from being able to get away from her piglets, for example if they bite her teats. Piglets are weaned and taken away from their mother when they are 3 to 4 weeks old, and even earlier in some countries.

Within a couple of weeks of weaning, the sow is inseminated again (often artificially) and starts her next pregnancy. Commercial sows normally produce just over 2 litters a year with around 10-12 piglets per litter. She has a breeding lifetime of about 2-3 years before being sold for slaughter and replaced.

Farrowing crates have been banned in Sweden, Norway, and Switzerland, and are being phased out in Germany and Austria, but are widely used in the rest of the world.

In intensive systems, sows are kept in barren environments with no opportunities to explore their environment, root around or build a nest.

Their strong maternal instinct to build a nest for their young has survived domestication and involves increased activity, such as searching for nesting materials, digging, and rooting out a shallow hollow, and constructing a suitable nest.

Their ability to fulfil these natural behaviours depends on their space allowance, the possibility of movement and access to suitable nesting materials - all of which are insufficient in farrowing crates which causes stress and frustration.

Feed is often restricted during pregnancy, causing chronic hunger, and increasing the frustration levels of pregnant sows.

In conventional feeding systems, pregnant sows are fed a concentrated diet made of 2-3kg of food a day, normally as one meal.

This provides little opportunity to ensure satiety and fulfil foraging needs, and leads to hunger which is associated with increased levels of aggression, physical activity, and the development of stereotypic behaviour (e.g. bar-chewing).

Sows are increasingly bred to be hyper prolific, to further increase the number of piglets born per litter. However, larger litters can lead to higher piglet mortality and can also compromise the welfare of the sow.

Litter sizes can be as large as 17 piglets and can cause pain and fatigue at the time of farrowing, as well as some piglets needing to be fostered by other nurse sows, breaking the mother-offspring bond.

Read more about free farrowing systems.

Fattening pigs are bred for their meat and are generally housed in barren, overcrowded sheds, often on slatted/concrete floors, without any comfortable bedding or material to root around in such as straw.

They have no outdoor access, and their confined, barren conditions means they are unable to perform natural behaviours and become bored and frustrated.

In overcrowded environments, they are also unable to move away or hide from other pigs, so they tend to fight and bite each other, sometimes causing severe injury, particularly to their tails.

Most piglets have their tails docked to prevent tail lesions due to tail biting, which is a painful procedure and generally performed without pain relief.

Stress, illness and conflict leading to tail biting often result when piglets are mixed with unfamiliar young pigs, in environments that prevent natural behaviours, leading to boredom and frustration.

Routine tail docking in pigs is currently banned by EU legislation but a series of recent audits carried out by the European Commission to assess the implementation of the Pig Directive have highlighted that in almost all EU countries, over 90% of meat pigs are routinely tail docked.

Read more tail docking and tail biting.

Soon after birth, the teeth of piglets are often clipped to reduce the risk of injuries caused by piglets biting each other, and their mother as they fight for the best teats.

Sows don’t always have enough milk to feed all their piglets, especially if they have large litters or their bodies are in poor condition.

Routine tooth resection, which includes teeth clipping as well as teeth grinding, is currently banned by the EU Pig Directive but it may still be practiced on a significant number of farms.

Read more tooth resection.

Within a week of birth, many male piglets are surgically castrated (although not in the UK and Ireland), usually without appropriate anaesthetic or pain relief, causing short and long-term pain. It also leaves the piglets more prone to infection from the open wound with limited immunity at such a very young age.

The main reason piglets are castrated is to prevent “boar taint”. This is a smell or taste of pork, caused by the sexual hormones testosterone and androstenone. Males that are not castrated may also be aggressive and show more sexual behaviour. This may cause injury to others if they fight or mount each other and can be dangerous to farm workers if they are aggressive during handling.

In some countries, pigs are reared to a heavier weight so that certain cuts of meat or fat content may be produced. This means there is more risk of boar taint because the pigs reach puberty, as well as the welfare risk of them injuring each other. Where rearing entire males is not practicable, there are other alternatives to surgical castration, such as Improvac.

Read more about piglet castration and the alternatives to castration.

Pigs do not have sweat glands and are particularly susceptible to heat stress during transport and pre-slaughter. Significant numbers of pigs die each year in transport or in lairage at slaughterhouses due to stress.

In some slaughterhouses, pigs are pre-slaughter stunned using a mixture of CO₂ at a high concentration which has been shown to be severely detrimental to pig welfare, as it causes a feeling of burning to the pigs’ lungs before they lose consciousness.