Pig welfare guidance

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

Section 2 – Additional specific recommendations

The following is intended to be read in addition to Section 1.

Natural service, artificial insemination and vasectomy

Paragraphs 28 and 29 of schedule 1 of the Welfare of Farmed Animals (Scotland) Regulations 2010 state that:

28.—(1) Natural or artificial breeding or breeding procedures which cause, or are likely to cause, suffering or injury to any of the animals concerned must not be practised.

(2) Sub-paragraph (1) does not preclude the use of natural or artificial breeding procedures which are likely to cause minimal or momentary suffering or injury or that might necessitate interventions which would not cause lasting injury.

29. No person may keep an animal for farming purposes unless it can reasonably be expected, on the basis of its genotype or phenotype, that it can be kept without detrimental effect on its health or welfare.

163. Breeding programmes should pay at least as much attention to improving health and welfare as to production criteria. Ideally, the conservation or development of breeds of pigs which would limit or reduce animal welfare problems should be encouraged where possible. Where modern commercial genetic lines which produce larger live litter sizes are used, staff should have sufficient expertise and resources to cope with these, and particular attention should be paid to keeping sows in good condition.

164. All boars should have good and safe conditions in which to mate. Slatted floors and slippery conditions underfoot are not suitable for mating animals. As part of a health and welfare plan, avoidance of injury to boars and sows through excessive mating activity should be discussed with the owner’s / keeper’s veterinary surgeon.

Paragraphs 5 (1), 6 (1)and 6 (3)(b) of schedule 6 of the Welfare of Farmed Animals (Scotland) Regulations 2010 state that:

5.—(1) A pig must be free to turn round without difficulty at all times.

6.—(1) The dimension of any stall or pen used for holding individual pigs in accordance with these Regulations must be such that the internal area is not less than the square of the length of the pig, and no internal side is less than 75% of the length of the pig, the length of the pig in each case being measured from the tip of its snout to the base of its tail while it is standing with its back straight.

6.— (3) Sub-paragraph (1) does not apply to a pig held in a stall or pen—

(b)for the purposes of service, artificial insemination or collection of semen;

provided that the period during which it is so kept is not longer than necessary for that purpose.

165. Sows should be kept in their groups until insemination, at which time they can be moved to an appropriate stall or pen and inseminated. Sows should be allowed time to settle down in the stall or pen, and then exposed to a boar in order to encourage the standing reflex before artificial insemination takes place. It is not acceptable for sows to be left for long periods of time in insemination pens in which they cannot turn around easily, either before or after insemination. The total period in the insemination pen should not exceed 4 hours.

166. Sows should be left undisturbed, to allow uterine contractions to stop after artificial insemination (and natural service). They should then re-join their group in order to minimise bullying within the group hierarchy. If a sow is to be inseminated more than once, she should return to the group after each occasion.

167. Semen collection and artificial insemination should only be carried out by a trained, competent and experienced operator. Vasectomy must only be carried out by a veterinary surgeon.

Farrowing sows and piglets

Paragraphs 22 to 27 of schedule 6 of the Welfare of Farmed Animals (Scotland) Regulations 2007 state that:

22. Pregnant gilts and sows must, where necessary, be treated against external and internal parasites.

23. If they are placed in farrowing crates, pregnant sows and gilts must be thoroughly clean.

24. In the week before the expected farrowing time, sows and gilts must be given suitable nesting material in sufficient quantity unless it is not technically feasible for the slurry system used.

25. During farrowing, an unobstructed area behind the sow or gilt must be available for the ease of natural or assisted farrowing.

26. Farrowing pens where sows are kept loose must have some means of protecting the piglets, such as farrowing rails.

27. In the week before the expected farrowing time and during farrowing, sows and gilts may be kept out of sight of other pigs.

Paragraphs 35 to 39 of schedule 6 of the Welfare of Farmed Animals (Scotland) Regulations 2010 state that:

35. If necessary, piglets must be provided with a source of heat and a solid, dry and comfortable lying area away from the sow where all of them can rest at the same time.

36. The part of the total floor where the piglets are kept, and which is large enough to allow the animals to rest together at the same time, must be solid or covered with a mat or be littered with straw or any other suitable material.

37. Where a farrowing crate is used, the piglets must have sufficient space to be able to be suckled without difficulty.

38. Piglets must not be weaned from the sow at an age of less than 28 days unless the welfare or health of the sow or piglets would otherwise be adversely affected.

39. Piglets may be weaned up to 7 days earlier if they are moved into specialised housings which are emptied and thoroughly cleaned and disinfected before the introduction of a new group and which are separate from housing where sows (other than weaners) are kept.

168. Owners / keepers should manage the feeding of sows and gilts so that they are in a suitable body condition at the time of farrowing. See paragraphs 59 and 60.

169. Sows and gilts should be moved into farrowing accommodation at least 48 hours, and ideally up to 5 days, before expected delivery. This is especially important for allowing gilts time to settle, and for giving both sows and gilts the opportunity to nest build in the pre-farrowing period, and thereby minimising stress. Sufficient suitable nesting material must be provided, particularly in the 48 hours prior to farrowing. (The only exception to this is in cases where it is not technically feasible for the slurry system used.) Nesting material is in addition to any environmental enrichment material already provided. See paragraphs 88 to 99.

170. Ideally, indoor farrowing accommodation would be well designed zero-confinement systems which can provide similar piglet survival to conventional permanent farrowing crates if carefully managed. Temporary confinement systems allow the sow to be unconfined pre-farrowing but then confined around the critical period for piglet survival before the crate is opened up during lactation to allow the sow to turn around. If temporary crates are installed as part of a planned progression to fully free farrowing, the pens should be large enough to accommodate a future free farrowing system - current recommendations are a minimum total pen size of 7.8m2 (see Annex 3).

171. In indoor free farrowing systems where the sow is not confined, the sow should have sufficient space to allow her to nest build, to turn around, rise up and lie down again, as well as access feeding and dunging areas without difficulty. Farrowing rails, sloped walls or other means to protect piglets from crushing must be incorporated into the pen design. When any procedures need to be carried out on the piglets, the pen design, where possible, should allow for the sow to be separated in an area of the pen away from her piglets or for the piglets to be shut away from the sow. A separate and easily accessible creep area may facilitate this. (See Annex 3 for further information on free farrowing.)

172. Where the sow is confined in a farrowing crate, it should be large enough to accommodate her and to allow her to rise and lie down without difficulty, and should be easily accessed in an emergency. The crate length should be sufficient to allow her to lie laterally with her head in contact with the floor and allow space for farrowing. The sow should be confined in a crate for the minimum time necessary following farrowing, and not after she has finished suckling piglets. Where the farrowing crate incorporates a design that can be opened up to allow the sow to turn freely, this should be carried out as soon as practicable for the individual sow and litter, ideally by four days and no more than seven days after farrowing, unless on veterinary advice there is an overriding health or welfare reason to alter this.

173. In all farrowing accommodation, the piglets should have sufficient space to allow them to be suckled without difficulty.

174. All farrowing accommodation should be clean and dry upon entry. Pregnant sows and gilts must be thoroughly clean before being moved into farrowing crates. In order to minimise infection risks, the farrowing environment should be designed so that the sow and her piglets stay clean and dry throughout lactation.

175. The thermal comfort zones of the sow and her litter are considerably different and the specific conditions at the time should be taken into account. See also paragraphs 100 to 113.

176. Where overhead lamps / heaters are used they should be securely fixed, checked regularly to reduce the fire risk, and protected from coming into contact with, or interference by, the sow or piglets.

177. Owners / keepers should be experienced and competent in the techniques of farrowing and the farrowing system being used (free or crate). If converting to a new system, it will take some time to become familiar with it, and suitable training or advice should be sought as appropriate. Cleaning, disinfection and hygiene at farrowing are essential and procedures for assisted farrowing should be documented in a health and welfare plan.

178. There are proposals to phase out farrowing crates, and any new system should protect the welfare of the sow, as well as her piglets. Owners / keepers should consider alternative systems when designing new facilities, and seek expert advice to support decisions. A large volume of information from research and practical implementation of free farrowing systems can be found on the free farrowing hub. (See Annex 3)

Matching litter size and milk production

179. Supporting sows to produce sufficient milk will help ensure that all piglets can be fed, thus reducing the need for fostering. It will also reduce the risk of piglets fighting, and so reduce the need for teeth clipping / grinding (see paragraphs 157 to 161). Sows that have experienced problems with insufficient milk production should not be bred from.

180. Sows that experience exhaustion and stress at farrowing are likely to produce less milk and may have problems with milk let down. Ensuring good sow body condition, thermal comfort, suitable feeding during the transition to lactation accommodation, avoiding mastitis and ensuring sufficient water intake are all important. Ideally, breeding companies should ensure that milking ability and mothering capability are selected for alongside sow prolificacy and also consider the impact of increased prolificacy on sow and piglet health and welfare.

181. Avoiding the use of genetic lines of pigs that routinely produce average live litter sizes greater than the number of functional teats available would reduce the need for cross fostering, and would be likely to reduce piglet mortality, increase piglet weaning weights, reduce variability in piglet weights and reduce the need for farrowing crates, all of which improve pig welfare. Where more prolific modern commercial genetic lines are used to increase overall productivity, greater care and expertise are required and keepers should work with their veterinary surgeon and other professional advisors to ensure that appropriate birthweights and pre-weaning mortality targets are met.


182. There are various different circumstances when fostering may be necessary and potential welfare issues for both the nursing sow and the piglets need to be carefully considered. Traditional cross-fostering techniques involve transfer of small numbers of piglets between litters to even up litter sizes. More recently developed practices involve transfer of whole litters to and from a nurse sow, and sometimes the use of an intermediate nurse sow as well.

183. A nurse sow is a lactating sow whose piglets have weaned (often early) or are fostered onto another sow, and who is then used to suckle surplus piglets from another sow. An intermediate sow is a sow selected approximately 7 days into her lactation to have her piglets fostered off her and onto another sow – the nurse sow – who is approximately 21 days into her lactation. This is done so the intermediate sow can then foster the surplus neonatal piglets (approximately 24 hours old) from large litters.

184. Procedures should be agreed with a veterinary surgeon or expert advisor. This should include suitable measures to reduce piglet mortality risks, prevent disease introduction and spread, and minimise any distress to piglets and / or sows. The welfare of other piglets in the litter needs to be considered, including the need to avoid fighting and competition.

185. Where nurse sows are used an appropriate sow should be selected. The nurse sow should have an udder that fits the nursing piglets: small teats for small piglets, large teats for larger piglets. It is important to check whether the pen partitions obstruct the piglets’ access to the udder. The nurse sow, and especially the intermediate nurse sow, should have a good body condition score and a healthy appetite to be able to handle the extra nursing period. The nurse sow and intermediate nurse sow should have taken good care of their own piglets, so that they have a proven good milk yield. A nurse sow should not be given more piglets than she had previously; the nurse sow and the intermediate nurse sow do not have more active mammary glands than the number of piglets removed from them.

186. If nurse sows are likely to continue nursing beyond the standard 4-5 week period, the use of an alternative, non-crating, system is highly recommended. If held continuously in a farrowing crate, this period should not be extended beyond 7 weeks including the pre-farrowing period.

187. Piglets should have received sufficient colostrum from their mother before being moved for fostering. Generally, nursing piglets should not be moved before 12 hours after birth and would ideally be moved within 36 hours. Sometimes 3-8 hours will pass before the nursing sow and intermediate sow give the piglets milk for the first time, and nursing piglets will need to be strong enough to wait that long. Alternative timings may however be appropriate in different circumstances as recommended by veterinary surgeons.

188. In a sectioned system, the nurse sow and intermediate sow should be moved to a pen in the section where the piglets were born. The nurse sow brings fewer pathogens than the piglets. The piglets are then weaned at the same time as the other piglets in the section.

189. Fostering onto artificial milk should not be regarded as a routine solution to problems with the piglets, and should only be used after other strategies have been tried. Strict hygiene measures should be followed when using automated milk machines for pigs and a high quality pig specific artificial milk should be used. Piglets must not be weaned from the sow at an age of less than 28 days unless the welfare or health of the sow or piglets would otherwise be adversely affected. However, as stronger, larger piglets may be better suited to artificial fostering systems with artificial milk, this could allow for some stronger piglets within a litter to be weaned earlier if necessary to protect the welfare of the sow or weaker littermates. Piglets can also be weaned up to 7 days earlier if they are moved into specialised housing which is emptied and thoroughly cleaned and disinfected before the introduction of a new group and which is separate from housing where sows are kept.

Weaners and rearing pigs

Paragraph 44 of schedule 6 of the Welfare of Farmed Animals (Scotland) Regulations 2010 states that:

44. The unobstructed floor area available to each weaner or rearing pig reared in a group must be at least—

(a) 0.15m2 for each animal where the average weight of the animals in the group is 10 kg or less;

(b) 0.20m2 for each animal where the average weight of the animals in the group is more than 10 kg but less than or equal to 20 kg;

(c) 0.30m2 for each animal where the average weight of the animals in the group is more than 20 kg but less than or equal to 30 kg;

(d) 0.40m2 for each animal where the average weight of the animals in the group is more than 30 kg but less than or equal to 50 kg;

(e) 0.55m2 for each animal where the average weight of the animals in the group is more than 50 kg but less than or equal to 85 kg;

(f) 0.65m2 for each animal where the average weight of the animals in the group is more than 85 kg but less than or equal to 110 kg; and

(g) 1.00m2 for each animal where the average weight of the animals in the group is more than 110 kg.

190. The unobstructed floor areas in the box above are absolute minimum requirements and are primarily intended for fully slatted floor housing. Other types of housing may require greater space allowances. Any ongoing changes in stocking density should be reviewed and recorded in the health and welfare plan. The lying area, excluding the dunging area, should be of sufficient size to allow all the pigs to lie down on their sides at the same time. There is evidence that increasing space allowance beyond the legal minimum can improve growth rate and benefit welfare by reducing restriction of movement, improving comfort, improving ability to express exploratory behaviour, reducing stress, and reducing the risk of abnormal behaviours (e.g. tail biting). See Annex 3.

191. Where part of the unobstructed area is on a different level, for example balcony systems for weaners, the design must comply with all other requirements of welfare legislation including:

  • suitability of flooring for the age of pig;
  • avoidance of injury risks from all new fixtures and fittings including ramps;
  • minimum lighting requirements in the covered areas;
  • system design which avoids dung and urine falling on pigs underneath balcony;
  • system design which allows all pigs to access all areas;
  • ability for owners / keepers to inspect all pigs at all times and remove sick or injured pigs without further injury.

192. Where any new pen design is planned which requires advice on compliance with the law, it is recommended that this is discussed with a veterinary surgeon or technical advisor. If there is any doubt it should be referred to APHA for an assessment. The impact of new pen design on the welfare of the pigs should be monitored, and any issues discussed with a veterinary surgeon or technical advisor and remedied.

Mixing of pigs and prevention of fighting

Paragraphs 40 to 43 of schedule 6 of the Welfare of Farmed Animals (Scotland) Regulations 2010 state that:

40. Weaners and rearing pigs must be—

(a) placed in groups as soon as possible after weaning; and

(b) kept in stable groups with as little mixing as possible.

41.— (1) If weaners and rearing pigs unfamiliar with one another have to be mixed, this should be done at as young an age as possible, and, where reasonably practicable, no later than one week after weaning.

(2) When weaners and rearing pigs are mixed they must be provided with adequate opportunities to escape and hide from other pigs.

42. The use of tranquillising medication in order to facilitate the mixing of weaners and rearing pigs must be limited to exceptional conditions and only after consultation with a veterinary surgeon.

43. When signs of severe fighting appear among weaners and rearing pigs, the causes must be immediately investigated and appropriate measures must be taken.

193. The health and welfare plan should include a strategy for managing mixing and establishing groups of pigs and for isolation of aggressors where necessary. The minimum amount of mixing should occur from weaning through to finishing. Aggressors should not be placed with sick or injured pigs.

194. For pigs being reared to onset of sexual maturity, owners / keepers should consider, with veterinary advice, how to manage aggression and unwanted sexual activity in finishing pigs as juvenile females start to come into oestrus. Split sex rearing may be appropriate.

195. Aggression can present a severe problem where boars, sows or gilts are kept in groups. The temperament of individual animals should always be considered when managing groups. Adequate space and providing opportunities for pigs to move away from aggressors are particularly important at the time of mixing breeding pigs. The health and welfare plan should include measures to be taken in the recording of, and solutions to address, any persistent bullying. Any animal suffering persistent bullying or carrying out persistent bullying must be removed from the group. See paragraphs 55 to 58.

Dry sows and gilts

Paragraphs 28 to 34 of schedule 6 of the Welfare of Farmed Animals (Scotland) Regulations 2010 state that:

28. Sows and gilts must be kept in groups except during the period between 7 days before the predicted day of farrowing and the day on which the weaning of piglets (including any piglets fostered) is complete.

29. On and after 1st January 2013, the pen where the group is kept must have sides greater than 2.8m in length, except when there are less than 6 individuals in the group, when the sides of the pen must be no less than 2.4m in length.

30. On and after 1st January 2013—

(a) the total unobstructed floor area available to each gilt after service and to each sow when such gilts or sows are kept in groups must be at least 1.64m2 and 2.25m2 respectively;

(b) when gilts after service or sows are kept in groups of fewer than 6 individuals the unobstructed floor area must be increased by 10%;

(c) when gilts after service or sows are kept in groups of 40 or more individuals the unobstructed floor area may be decreased by 10%.

31. On or after 1st January 2013, for gilts after service and pregnant sows, a part of the area required under paragraph 29 equal to at least 0.95m2 per gilt and at least 1.3m2 per sow must be of continuous solid floor of which a maximum of 15% is reserved for drainage openings.

32. Sows and gilts kept on holdings of fewer than 10 sows may be kept individually provided that their accommodation complies with the requirements of paragraphs 5 and 6.

33. In addition to the requirements of paragraph 13, sows and gilts must be fed using a system which ensures that each individual can obtain sufficient food even when competitors for the food are present.

34. (1) All dry pregnant sows and gilts must be given a sufficient quantity of bulky or high fibre food as well as high energy food to satisfy their hunger and need to chew.

(2) In this paragraph a reference to a dry pregnant sow is to a sow between weaning her piglets and the perinatal period.

196. Many different feeding systems exist. The aim of any feeding system should be to reduce stress and aggression at feeding times, whilst supplying the correct amount of feed. Feeding time can be a catalyst for aggression if sows and / or gilts in the same building or group are not fed at the same time. The exception are systems which allow the sow to choose when to eat. When feeding groups of sows or gilts by hand, it is important to try to reduce the time from the first to the last animal being fed and also to distribute the food to ensure all members of the group can obtain their allocation at the same time, with reduced interference from other pigs.

197. Where self-locking individual feeding stalls are used, they can only be included in usable floor area if they are permanently accessible and not manually locked closed. The stalls should be of sufficient size that the largest pig can fit in with no body part (e.g. tail) protruding. There should be a separate place where the pigs can lie together as a group. See the box on accommodation following paragraph 79.

198. Mechanical and computerised feeding systems need to be maintained regularly. Regular checking of the amount of feed delivered is recommended.

199. All dry pregnant sows and gilts must be given a sufficient quantity of bulky or high fibre food as well as high energy food to satisfy their hunger and need to chew. There should be 15-20% dietary fibre in the overall daily feed, and supplementary fermentable, soluble fibres or resistant starches should be offered, such as sugar-beet pulp or native potato starch. To satisfy the need to chew and forage, sows should have access to appropriate substrates such as straw. When sows transition from the dry sow house to the farrowing house, it is important to maintain high-fibre feeding to aid farrowing progression and reduce fatigue.

200. Sow and gilt body condition assessment should also be undertaken regularly regardless of the system. See paragraphs 59, 60 and 168.

201. Heavily pregnant females (beyond 90% gestation) should not be transported off the farm.


Paragraphs 19 to 21 of schedule 6 of the Welfare of Farmed Animals (Scotland) Regulations 2010 state that:

19. Boar pens must be sited and constructed so as to allow the boar to turn round and to hear, see and smell other pigs, and shall contain clean resting areas.

20. The lying area must be dry and comfortable.

21.— (1) The minimum unobstructed floor area for an adult boar must be 6m2 save as set out in sub‑paragraph (2).

(2) When boar pens are also used for natural service the floor area must be at least 10m2 and must be free of any obstacles.

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

Procedure: Tusk trimming

Purpose: Handler safety or herd welfare

202. Walls between pens should be high enough to prevent boars climbing and / or jumping into adjacent pens. Pens should be sited so that boars can see other pigs. Owners / keepers should not enter boar pens without a pig board and they should be able to escape easily from the pen if the boar becomes aggressive.

203. If the boar is kept with other boars or sows, measures need to be taken to prevent conflict, especially during feeding. If signs of severe fighting appear, the causes need to be immediately investigated and appropriate preventive measures taken. See paragraphs 193 to 195.

204. Boars are usually individually housed and need plenty of bedding material. In cases where this is not possible, a closely controlled environmental temperature is required. Extremes of temperature can lead to temporary infertility and may affect a boar’s willingness or ability to mate satisfactorily. As a guide, individual accommodation for an adult boar should have a floor area of not less than 7.5 m² if used for living purposes only. In a pen intended for mating purposes, the whole floor area should be kept dry, or sufficient bedding provided, to give adequate grip during service.

205. Requirements for enrichment material apply to boars as well as other pigs (see paragraphs 88 to 99).

206. Tusk trimming of boars is permitted if required for the purposes of handler safety or herd welfare.


Email: animal_health_welfare@gov.scot

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