Pig welfare guidance

Guidance about the needs of pigs and how to meet these needs in accordance with good practice.


Section 20 of the Animal Health and Welfare (Scotland) Act 2006 states that:

20 Mutilation

(1) A person commits an offence if the person—

(a) carries out a prohibited procedure on a protected animal, or

(b) causes a prohibited procedure to be carried out on a protected animal.

(2) A person (“person A”) who is responsible for an animal commits an offence if—

(a) another person carries out a prohibited procedure on the animal, and

(b) person A—

(i) permits that to happen, or

(ii) fails to take such steps (whether by way of supervising the other person or otherwise) as are reasonable in the circumstances to prevent that happening.

(3) A person commits an offence if the person takes a protected animal, or causes a protected animal to be taken, from a place in Scotland for the purpose of having a prohibited procedure carried out on the animal at a place outwith Scotland.

(4) In this section, references to the carrying out of a prohibited procedure on an animal are to the carrying out of a procedure which involves interference with the sensitive tissues or bone structure of the animal.

(5) This section does not apply—

(a) in relation to a procedure which is carried out for the purpose of medical treatment of an animal,

(b) in relation to a procedure which is carried out—

(i) for a purpose which,

(ii) in such manner as, and

(iii) in accordance with such conditions as,

the Scottish Ministers may by regulations specify, or

(c) in such circumstances as the Scottish Ministers may by regulations specify.

(6) Before making regulations under subsection (5), the Scottish Ministers must consult—

(a) such persons appearing to them to represent relevant interests, and

(b) such other persons,

as they consider appropriate.

Regulation 3 of the Prohibited Procedures on Protected Animals (Exemptions) (Scotland) Regulations 2010 states that:

Exempted Procedures

3. The Scottish Ministers hereby specify the procedures described in column 1 of each of Schedules 1 to 12 where the procedure is carried out in relation to the particular type of protected animal described in any of those Schedules and is carried out—

(a) for a purpose which is specified, in relation to any such procedure, in column 2 of the corresponding entry in the relevant Schedule;

(b) in hygienic conditions;

(c) in such a way as to minimise the pain and suffering it causes to the animal;

(d) in accordance with good practice; and

(e) where applicable, in accordance with such conditions as are specified, in relation to any such procedure, in column 1 of the entry in the relevant Schedule,

as procedures in relation to which section 20 (mutilation) of the Animal Health and Welfare (Scotland) Act 2006 does not apply.

129. Mutilations of pigs are generally prohibited under the Animal Health and Welfare (Scotland) Act 2006. Certain procedures (see Annex 2) are however allowed under the Prohibited Procedures on Protected Animals (Exemptions) (Scotland) Regulations 2010, provided that they are carried out by a person permitted to carry out the procedure and:

  • for the purpose specified in, and in accordance with, the schedules to these Regulations;
  • in hygienic conditions;
  • in such a way as to minimise the pain and suffering it causes to the animal; and
  • in accordance with good practice.

130. Mutilations can cause pain and distress to pigs and they should only be carried out having sought appropriate advice on possible alternative interventions in each case. See Annex 2.

131. Schedule 3 of the Veterinary Surgeons Act 1966 specifies treatments and operations that may be carried out by unqualified persons and who is permitted to carry them out in different circumstances.

Tail docking

Schedule 2 of the Prohibited Procedures on Protected Animals (Exemptions) (Scotland) Regulations 2010 states:


Procedure: Docking of farmed pigs kept on agricultural land

Purpose: Handler safety or herd welfare


1) The procedure may only be performed—

(a) where there is evidence that injuries to the tails of other pigs have occurred and where other measures to improve environmental conditions or management systems have been taken in order to prevent tail-biting; and

(b) by the quick and complete severance of the part of the tail to be removed.

2) Where pigs are older than 7 days of age the procedure must be performed under anaesthetic and additional prolonged analgesia and only by a veterinary surgeon.

132. Routine tail docking is not permitted. Tail docking should only be used as a last resort, after improvements to the pigs’ environment and management have proved ineffectual in preventing tail biting. Owners / keepers should document evidence of tail biting and keep records of the measures instigated and their effectiveness in improving the pigs’ welfare. Where records are not available and pigs are found to be tail docked, this may be considered in any decisions regarding the legality of the tail docking procedure being carried out by owners / keepers. Where breeding units are tail-docking in response to requests from finishing units, it is the owner’s responsibility to request this evidence from their supply units to justify any level of tail-docking on the breeding unit.

133. Written approval from a veterinary surgeon should be obtained before any tail docking is commenced. Confirmation from a veterinary surgeon should agree that, based on their veterinary risk assessment of the measures and management practices undertaken and records of tail biting and other associated records (for example slaughterhouse findings), tail docking is necessary and unavoidable for the particular batch of pigs in question or for a fixed period of time. This should be reviewed at least every 3 months. The veterinary surgeon should include what evidence has been reviewed in this written confirmation.

134. Owners / keepers should undertake a regular review of on-farm reports of tail damage and any such slaughterhouse reports and associated post mortem findings. The origins and the causes and control of tail biting will be specific to the individual farm and circumstances of outbreaks.

135. If tail docking has been used on a farm to prevent tail biting over several years, owners / keepers should consider changing monitoring and management procedures including space allowance, genetics and/or changes to the system in which the pigs are reared. Any new accommodation and slurry management systems should be designed to ensure that adequate appropriate enrichment material can be provided and other trigger factors for tail biting have been addressed to ensure tail docking is only seen as a last resort, non-routine measure. When designing and installing new accommodation, the appropriateness of the flooring should be an essential consideration, although it is recognised that tail biting can occur on any type of flooring where there are relevant contributory factors.

136. Where it is necessary, tail docking of pigs 7 days old or younger should be carried out by a trained and competent operator, using appropriate, well maintained, clean equipment. Where pigs are over 7 days old, tail docking must be carried out under anaesthetic, and with additional prolonged analgesia, by a veterinary surgeon. It is important that all equipment used should be cleaned and disinfected between litters of pigs.

Managing and reducing the risk of tail biting

137. Tail biting is a multi-factorial problem. Rather than being a fundamentally aggressive behaviour, it is likely that in most situations tail biting has its source in a pig’s basic need to root and forage, and is caused by that need, or another basic need, not being met. AHDB’s Tail Biting Web based Husbandry Advisory Tool (WebHAT) provides useful information about the key risks in pigs, and practical suggestions to help reduce them on farm. The EU Reference Centre for Animal Welfare’s review of the management of unweaned piglets also has useful information on early life risk factors for tail biting. (See Annex 3)

138. Ongoing monitoring of pig welfare and behaviour (see paragraphs 51 to 68) is important for identifying any risks before tail biting occurs, and addressing the underlying causes should improve health and welfare and promote positive well-being in the pigs. This in turn should ultimately reduce antibiotic use, mortality and carcase rejections, which should lead to improved productivity of the herd. Routine management procedures and expected monitoring / recording requirements for tail-biting risks should be specified, for example in the health and welfare plan. (See paragraphs 13 to 14.)

139. Decision making around management / husbandry measures all require skill and commitment from staff in performing these tasks competently, for example: management of ventilation; thermal comfort; manner of feed and water supply; contingency planning for rectifying failures in food, water, and ventilation; management of enrichment materials; choice of pig genetics; tail-length variation; mixing pigs; picking up on early signs of tail biting and fighting / aggression; identifying tail biters or tail bitten pigs; removing the biter when identified; and hospital pen management in the early stages of an incident.

140. To help owners / keepers find the solutions and management strategies that work best on a particular farm, a number of elements should be evaluated and where necessary changes made, with the advice of a veterinary surgeon and / or scientific / technical specialist in tail biting. This evaluation should include consideration of farm management, including the knowledge, skills, attributes and attitudes of the stock-keepers, as well as the pigs themselves. Factors to consider include:

1. resources or ‘inputs’ – such as pen structure, space allowance, fittings, diet and environmental enrichment material and quantity;

2. environmental outcome measures – such as thermal comfort (temperature and relative humidity, temperature changes, draughts), air quality (for example ammonia, dust, carbon dioxide levels) and light levels; and

3. animal based outcome measures – such as health / disease, including injuries; cleanliness; positive and negative behaviours (for example play, aggression, chewing / biting other body parts); and competition for feed / water access.

Some of these factors are expanded upon in more detail in the paragraphs below.

Resource factors:

Pen structure, cleanliness and space

141. A dirty environment reduces the comfort of a living area and increases levels of noxious gases, stressing the pigs and increasing the risk of disease. It can also be more difficult to assess early signs of ear, flank and tail biting when pigs are dirty. It is important to have well-defined areas for resting, feeding and dunging. Potential indicators of an unsuitable pen structure or lack of cleanliness, which could increase the risk of tail biting are:

  • presence of manure on the pigs’ bodies. Dirty pigs could be a potential indicator of a suboptimal environment, poor nutrition or disease (except in warm weather when pigs may wallow); and
  • increased disease (lameness, diarrhoea, respiratory infections, secondary infection of skin wounds).

Lack of sufficient space can also increase the risk of tail biting so consideration should be given to reducing stocking density if signs of biting are seen.

Enrichment material

142. Environmental enrichment is the process of improving and enhancing the environment that pigs are reared in by stimulating natural behaviours to explore and forage that pigs are highly motivated to perform. This often involves adding complexity and additional materials to the environment. This should then reduce stress and injurious behaviours such as tail-biting in pigs or fighting between pigs. Potential indicators of ineffective or insufficient enrichment material, which could increase the risk of tail biting, are:

  • bitten tails and ears;
  • skin lesions;
  • loss of interest in enrichment materials over time;
  • biting pen fittings or other pigs instead of enrichment materials;
  • rooting in and manipulating dung;
  • competition or fighting for use of enrichment materials; and
  • belly-nosing.

Some of the above indicators may also be associated with other risk factors. Any risk assessment should consider all identified risks on the farm and at any source breeding units where appropriate. See paragraphs 88 to 99.


143. Pigs need feed of adequate consistency, as well as the right levels of minerals, fibre and essential amino acids. They also need a sufficient quantity of fresh, good quality water. Good intestinal health means fewer cases of diarrhoea, healthier pigs, higher daily gain, better feed conversion and less use of antibiotics. Potential indicators of an unsuitable diet, which could increase the risk of tail biting, are:

  • low body condition or body fat measure;
  • variation in weight;
  • poor carcase classification; and
  • poor gut health including stomach and intestinal ulcers.

144. A correctly balanced feed will help keep pigs healthy and ensure good gut condition. Pigs that have to adapt suddenly to new feed may become stressed, and may turn to tail biting. Avoiding lengthy periods between feeds, delivering the feed in ways that increase the time taken to eat a meal and (where appropriate) increasing the roughage content can also be beneficial in reducing the risk of hunger, frustration and, as a result, unwanted behaviours.

Environmental outcome measures:

Thermal comfort, air quality and light

145. Pigs need a stable environment that is close to their optimum temperature and humidity, draught-free and with suitable lighting conditions. Maintaining the right temperature and good air quality is extremely important in keeping stress levels low. If pigs are not comfortable, they may become aggressive and may begin tail, leg, flank or ear biting. See paragraphs 100 to 113.

146. In cold weather, insulation, sufficient bedding or a heating system can ensure thermal comfort. During warm weather, options include air conditioning, floor cooling, misting and drip systems, showers and wallows.

147. Limiting the flow of cold air over sleeping areas is important as well as keeping dust and ammonia levels to a minimum. It is also important for pigs to be able to avoid direct sunlight. Continuous lighting causes stress and is not permitted. Very bright lights should be avoided. For direct sunlight, the solution could be as simple as fitting blinds or white washing the windows. Keeping pigs in semi-darkness to avoid fighting is ineffective and is not permitted. See paragraph 114, and the legislation box in relation to lighting.

Animal based outcome measures:

Health and fitness

148. Ensuring good overall health is another way to help avoid tail biting. A pig in poor health is a stressed pig.

149. Indicators of poor health that could increase the risk of tail biting are:

  • bitten or limp tail;
  • skin lesions or scratches;
  • increased restlessness;
  • lameness;
  • lack of appetite;
  • panting, shivering, hair standing on end, coughing, sneezing, diarrhoea;
  • abnormal body size or shape, or reduced weight gain;
  • social isolation;
  • absence of / reduction in play behaviour;
  • secondary skin infection and necrosis of wounds;
  • increased mortality.

150. A comprehensive health and welfare plan, regular monitoring by the stock-keeper and regular visits by a veterinary surgeon are important for maintaining the overall health of pigs and avoiding clinical outbreaks of diseases on the farm / premises.


151. There should be sufficient space in each pen, relevant to the system in use, to avoid competition between pigs for access to and use of resources, such as food, water, enrichment items and bedding area. For example, for food and drink sufficient trough space and numbers of drinkers should be provided. Likewise, there should be sufficient enrichment items to avoid competition between pigs. Potential indicators of insufficient resources, which could result in competition and thereby increase the risk of tail biting, are:

  • poor body condition;
  • variability in body size within a pen;
  • skin lesions on hind quarters (food competition);
  • skin lesions on forequarters (space competition);
  • increased aggression, for example fighting around feeders;
  • pigs crowding around feeders and / or drinkers;
  • poor distribution of pigs in each area of the pen; and
  • tail tucking around resources.

Identifying, monitoring and managing tail biting incidents

152. If a tail biting or other aberrant behaviour occurs, it is important to identify the potential causes early:

  • If possible, correct the deficiencies;
  • remove the biter(s) (if they can be identified), remove the bitten pigs and treat injuries or take other management actions on veterinary advice; and
  • provide distraction by adding fresh enrichment material such as rope, fresh wood or straw. Consider keeping an extra supply of enrichment material for emergencies.

153. All known risk factors should be considered and recorded, and suitable management changes should be made in those areas identified as being at risk. It can spread quickly through the pen and the severity of injury caused can increase very quickly.

154. There are multiple causes of tail biting and in order to understand why the problem is occurring, a systematic way of monitoring and recording incidents and possible causes should be developed and be part of a health and welfare plan. Monitoring should be increased as appropriate.

155. If improvements are not successful in stopping tail biting, then a reassessment of the measures introduced, and the system overall, should be made to identify areas where further suitable changes need to be made. Veterinary advice should be sought, as necessary, as to whether tail docking should be employed as a last resort, depending on the severity of the outbreak.

156. This process of reassessing and identifying successful measures should continue until tail-biting behaviour is consistently no longer seen. A plan for rearing pigs with undocked tails should then be developed with the veterinary surgeon, alongside suitable contingency planning to manage any future outbreaks of tail biting.

Teeth clipping / grinding

Schedule 2 of the Prohibited Procedures on Protected Animals (Exemptions) (Scotland) Regulations 2010 states:


Procedure: Uniform reduction of the corner teeth of farmed piglets kept on agricultural land aged 7 days or less by grinding or clipping to leave an intact smooth surface

Purpose: Herd Welfare


The procedure may only be performed where there is evidence of injuries to sows’ teats or to other pigs’ ears or tails and when other measures have been taken to prevent tail-biting and other vices have been exhausted.

157. Piglets compete aggressively with their litter mates for a particular teat on the sow. As piglets are born with sharp teeth, this may result in injuries to the piglets’ faces and to the sows’ udders. Injuries are reduced if sows are lactating well and have sufficient functional teats for all piglets in the litter.

158. Ensuring sows are lactating well involves paying attention to their nutritional and environmental needs to ensure good body condition and minimise stress. In cases where large litters are produced, nursed litter size can be reduced with fostering interventions: fostering piglets from large litters to a sow with a smaller litter may help reduce injuries. See section 2, below, on farrowing sows and piglets for more detailed guidance on these issues.

159. Routine clipping or grinding of teeth is not permitted. Owners / keepers should work with their veterinary surgeon and other professional advisors on management and health strategies to ensure that tooth reduction is not necessary. Where tooth reduction has to be performed as set out in the above legislation, it should always be considered a last resort, after other actions have been considered and taken to address the issue. If owners / keepers are carrying out tooth reduction on the farm unit, the health and welfare plan should identify the specific circumstances where tooth reduction may be necessary, and incidences should be recorded, along with the measures that were taken in the first instance to address the issue.

160. Teeth should not be clipped or ground to the gum line. Tooth reduction can cause short term pain and may cause long term pain if teeth are fractured due to poor technique, or if the pulp cavity of the tooth is exposed. Local infection, joint infection, and other potentially serious issues can result.

161. Suitable sharp, clean clippers or an appropriate clean grinder should be used. All equipment should be cleaned and disinfected between litters. Risk of injury and infections occur with both methods and appear more related to the proficiency of the operator than the procedure used (clipping or grinding). Staff should be trained and competent to carry out the task and only the tip of the teeth should be clipped or ground, taking care not to expose the pulp cavity in either procedure.


Schedule 2 of the Prohibited Procedures on Protected Animals (Exemptions) (Scotland) Regulations 2010 states:

Procedure: Castration

Purpose: Controlling reproduction or general animal management


1) Castration may only be performed by means other than the tearing of tissues.

2) Where pigs are older than 7 days of age the procedure must be performed under anaesthetic and additional prolonged analgesia and only by a veterinary surgeon.

162. Owners / keepers should consider carefully whether surgical castration is necessary. Castration is a mutilation and should be avoided wherever possible. If castration is necessary, the legislation requires that it must be performed under anaesthetic and additional prolonged analgesia if the pigs are older than 7 days of age. However, it is advisable that analgesia, and ideally local anaesthesia, are also used where pigs aged 7 days or less are castrated. Possible alternatives to surgical castration include use of an immunocastration vaccine.


Email: animal_health_welfare@gov.scot

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