Ethics in pig farming

Hi Readers,

After a long period of revision and exams I am back and very excited to start my many weeks of work experience I have lined up this summer!

Today I’m going to be investigating pig farming as I always ensure I do some research into any new animal before working with them on work experience. I’m so glad I have the chance to work with such intelligent creatures in the summer and want to also look into the breeding of these animals and how they are kept beforehand.

It was brought to my attention that there are lots of laws and regulations on pig farming when listening to a talk on “Compassion in World Farming” in my school by Eileen Greeves that must be adhered to when keeping pigs.

The topics included are: Pig housing and design (making sure they have enough material to investigate and have the ability to stand up, lie down and rest without difficulty and able to see other pigs at all times), Feeding and watering pigs (making sure they’re fed at least once a day and have the correct amount of water available to them dependant on their size), Health and welfare (getting any necessary medical treatment at the correct time and dose), Protecting animals from hazards and emergencies (stock should be moved to a more suitable area if there’s no natural or artificial shelter to protect grazing stock from extreme weather – heat waves, flooding or being buried by snow).

However what caught my interest was the following criteria.

Mutilating pigs

Boar tusks

Boar tusks should only be reduced in length when there’s evidence that it’s needed to prevent injuries to other animals/for safety reasons.


Pigs shouldn’t be castrated wherever possible and other ways should be used to reduce aggression and avoid boar taint. Boar taint is an unpleasant smell that is smelled during the heating of pork. Boar taint occurs particularly in meat of adult male pigs due to changes in the hormonal system when the animal is growing older. Boar taint rarely occurs in female pigs or castrated male pigs. Research has shown that there are three  substances that can cause boar taint: androstenone, skatole and indole. Androstenone – substance that is important in the development of the sperm cells in male animals. Skatole – produced during the degradation of certain amino acids in the body. Skatole – affects both male and female animals. Castration of male piglets lowers the concentration of Skatole significantly.

If castration must be done, a method must be used that doesn’t involve tearing tissues. Farmers can castrate pigs up to 7 days old, as long as they’ve been trained to do so – older pigs must be castrated by a vet.

Tail docking

Pigs should be separated or stocking densities cut down to reduce aggression. If those methods fail then tail docking should be a last resort on pigs over 7 days old and must be:

  • carried out under anaesthetic and additional prolonged analgesia (painkillers)
  • carried out by a vet
  • done by a quick and complete cutting of the tail

Tail docking is performed to reduce tail biting and cannibalism among pigs.

Teeth clipping

Corner teeth shouldn’t be routinely reduced in piglets. Only if there’s evidence that they’re injuring a sow’s teats or other pigs’ ears or tails, and farmers are trained to do so, can they do this.

Carrying out grinding or clipping routinely is not allowed. When steps have been taken to improve the environment or management of pigs to prevent tail biting but there’s evidence it’s still happening, you can carry out grinding or clipping. But this should only be:

  • done in the first 7 days of the piglet’s life
  • a uniform reduction of the corner teeth

Nose rings

It is not allowed to put nose rings in pigs kept continuously in indoor housing systems.


In reading these rules and measures put in place to prevent certain behaviours in particular I have found that pigs can be rather aggressive compared with similar sized animals I have worked with (ie. sheep). I researched this a little more and found there are a few reasons for this. Piglets show aggression to other piglets within the first week of life while forming a teat order (they always suckle the same teat so much form this teat order). Introducing new pigs into a group may lead to aggression as the pigs establish social ranks. Pigs may spend 1–2 minutes nosing each other, vocalising, and then biting until one of the pigs retreats. It may take several days to establish a hierarchy in older pigs.

Crowding and limited amounts of food increase aggression. During breeding, boars may fight and become very vocal; boars will strut shoulder to shoulder, champ their jaws (producing pheromone-rich saliva), then finally face each other and attack. Serious injuries may result, especially among boars that still have their tusks. Breeds with lower body fat are more aggressive when handled.

Tail biting was one of the behaviours that really caught my attention. Tail biting is seen mostly in confined pigs. Overcrowding and boredom seem to be the main causes. Free-ranging pigs spend 5–10 hours daily looking for food and rooting, whereas pigs kept in pens consume meals in a short time. Slatted floors without bedding, low-salt diets, and low-iron soil seem to prompt pigs to start tail biting. Once the problem starts, blood from the injured tail seems to arouse the other pigs and can even lead to death of the victim however it rarely advances to pure cannibalism.

In terms of cannibalism, this is seen in first time mum gilts (young female pigs), cannibalism accounts for 4% of piglet deaths and is estimated to affect about 18% of litters. It is most common immediately after giving birth when the sow is stressed. Usually, the sow will bark to warn piglets walking by her head and then later attack them, biting them to death. This may raise some ethical questions such as should they become so stressed that they resort to killing their young? Can this be helped? Does it happen in smallholdings where space isn’t so much of an issue? From a veterinary point of view, how could we ensure that in farms that number decreases in order to help farmers produce as many piglets as possible?

I look forward to working with such a different species and hope I learn more about their behaviour in a commercial setting. As always, thoughts and personal experiences are very much welcomed in the comment section.





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