Organic New Zealand 62, no. 1, Jan/Feb 2003, 38-39.

Sow stalls and farrowing crates – ethically, scientifically and economically indefensible

Michael C. Morris,
Environmental studies, School of Earth Sciences, Victoria University of Wellington, P O Box 600, Wellington.

Last year, the Ministry of Agriculture invited submissions on the Code of Welfare for pigs.  This gave animal welfare/rights groups the opportunity to organise a nation-wide lobbying campaign to place a legal ban on current unacceptable practices, particularly the confinement of sows in sow stalls and farrowing crates.

These bare, narrow cages, approximately 0.7m wide and 2.0m long, confine the sow to the degree that she cannot turn round. The purpose of the sow stall is to maximise the number of sows in a given area, increase the pregnancy rate and litter size, reduce labour costs, and mitigate husbandry problems associated with aggression. Pigs are kept in farrowing crates to prevent them from rolling on to piglets and crushing them.  In some cases, sows spend their entire adult life in close confinement, being moved from sow stalls to farrowing crates during each reproductive cycle.

Animal welfare/rights groups have argued that these intelligent and sensitive animals suffer psychological stress and boredom from not being able to display normal patterns of  behaviour typical of the species, and that causing such intense suffering merely for economic gain is quite simply, morally wrong.

Intensive pig farming requires huge amounts of antibiotics to prevent contagious diseases resulting from crowding, so it is not an option for organic pig farmers.  The improved welfare conditions that organically farmed pigs enjoy as a result of this restriction provides both a further justification for organic animal production, and another selling point for those wishing to promote the advantages of organics to a public increasingly concerned with animal welfare.

Scientific arguments
There is a tendency among some influential scientists to dismiss anything that cannot be measured under repeatable laboratory conditions as "unscientific".  One such group of scientists argued that sow crates should be continued during the first 4 weeks of pregnancy because of a lack of "scientific" evidence that the pigs were suffering (1).

Nevertheless, there are other scientifically valid means of approaching the study of animal welfare, such as comparisons with human behaviour, and objective measurements of how much work animals are prepared to put in for an improvement in conditions.  If these methods are applied to the issue of severe confinement in pigs, a totally different picture emerges.

 Sow behaviour in crates, stalls and outdoors
A great many studies have confirmed that sows in sow crates show repetitive behaviour such as bar-biting, head weaving and tongue rolling (oral stereotypes), but when kept outdoors, or when confined together in larger pens, such stereotyped behaviour is absent (2).  Sows in crates have also shown behaviour indicative of learned helplessness – they have remained totally passive when poked and prodded, and even when a bucket of water was spilt on them (3).  In the opinion of Colin Spedding, chairman of the Farm Animal Welfare Council, the presence of such stereotyped behaviour is an indication that the animal is going insane (4).

Evidence suggests that pigs have a strong instinctive desire to root and forage, and therefore become bored and frustrated in the barren conditions of close confinement.  The provision of rooting material such as straw has been observed to reduce stereotypical behaviour (5) and aggressive actions such as tail biting (6).

Sows also have an instinct to make a nest before birth, as evidenced by the amount of work a pig is prepared to do to gain access to nesting material.   If this instinct is thwarted by confining pregnant sows in crates with no bedding, the results include acute stress,  reduced interaction with piglets and increased restlessness (7).

It has often been stated that farrowing crates are necessary to reduce the mortality of piglets, who would otherwise be crushed by the sow lying on top of them.  However,  a comparison between figures from Sweden (where farrowing crates are banned), and Denmark (where they are allowed) revealed no significant difference between mortality rates (8).

Reducing aggression
Supporters of sow stalls and farrowing crates often maintain that sows need to be confined to isolate aggressive individuals, or to protect sows from being bullied.   The need for occasional solitary confinement however in no way specifies that this confinement needs to be so extreme that the sow is unable to turn around or express normal patterns of behaviour.  There is also ample evidence to suggest that aggression can  be reduced to acceptable levels through improved husbandry in group housing systems.

Aggression can be reduced by providing nutritionally adequate food with fibre  to prevent feelings of hunger (9).  Pigs should not be overcrowded (10), adequate ventilation should be provided, and rooting material must be available (11). Pigs should be provided with a separate dunging area, to accommodate their inbuilt repugnance to lying in their own excrement.  Stock handlers can also be trained to best practice standards that can reduce the risks of aggression (12). If these provisions fail to reduce aggression to such an extent that welfare is compromised, then offending individuals can be housed individually in pens as an emergency measure.

Economic issues
The scientific evidence that sows suffer in crates and stalls is overwhelming.  When combined with our ethical duty to prevent physical and psychological suffering in self aware animals, the case for a complete ban on sow stalls is very strong.

One consideration that still needs to be taken into account however, is the practicality of a ban in economic terms, since unfortunately, the Animal Welfare Act allows economic considerations to override our ethical obligations to animals .  Here again however, the evidence for banning intensive confinement is strong.
 A recent survey of larger New Zealand pig farms revealed that that 51% of pork producers currently manage to produce pork without using the sow stall at all (13).  These farmers have undertaken this transition voluntarily and receive no subsidies or any price premiums on their product, yet are able to successfully compete in  an  unregulated market against those pork producers who still use the stall.

Economic data from EEC countries also reveals that fears of massive price rises resulting from a ban in intensive confinement are greatly exaggerated.  Converting a Dutch farm from stalls to group housing, with individual pens for  lactating sows and the provision of 300g of straw per sow per day, would add only about 3.5% to the production cost (14).   A detailed analysis of economic data from France, Netherlands, Denmark and the United Kingdom, led the conclusion that the extra cost of providing group housing with straw is 1.5-1.8p per kilogram of pig meat.  If this is passed on to the consumer, the additional cost would be a mere 36-95p per year (15).

It could still be argued that even a small price rise could result in consumers switching to other forms of meat, or to buying imported pork from countries that have fewer animal welfare restrictions.  However, a recent Colmar Brunton Poll revealed that the public were overwhelmingly in support of a complete ban on severe confinement, and are therefore likely to choose welfare friendly pork products if the production method and country of origin are clearly labelled on the packaging.  Organic certifying bodies could assist in this scheme by making it clear that organically farmed pork cannot be produced under severe confinement conditions.

One valuable tool in educating the public to choose welfare friendly pork products is a robust information resource that is capable of supporting such decisions against counter interests. We hope that this paper goes some way towards providing such information,  and that it can be used for the purpose of freeing sows from their solitary confinement.

 1.  Barnett, J.L., Hemsworth, P.H., Cronin, G.M., Jongman, E.C. and Hutson, G.D. (2001)  A review of the welfare issues for sows and piglets in relation to housing.  Australian Journal of Agricultural Research 52, 1-28.

 2.  SVC (Scientific Veterinary Committee) (1997)  The welfare of intensively kept pigs.  Report of the Scientific Veterinary Committee.
 Op cit., note 1.

 3.  Spedding, C. (2000)  Animal welfare.  Earthscan, London.

 4.  Whittaker, X., Edwards, S.A., Spoolder, H.A.M., Lawrence, A.B.  and Corning, S.  (1999). Effects of straw bedding and high fibre diets on the behaviour of floor fed group-housed sows. Applied Animal Behaviour Science 63, 25-39.  Kelly, H.R.C., Bruce, J.M., English, P.R., Fowler V.R.  and Edwards, S.A.  (2000) Behaviour of 3-week weaned pigs in Straw-Flow®, deep straw and flatdeck housing systems. Applied Animal Behaviour Science 68, 269-280.

5.   Schrøder-Petersen, D. and Simonsen, H.B. (2001) Tail biting in pigs.  The Veterinary Journal 162, 196-210.

 6.  Op cit., note 2.  Jarvis, S., Van der Vegt, B.J., Lawrence, A.B., McLean, K.A. Deans, L.A., Chirnside, J. and Calvert, S.K. (2001)   The effect of parity and environmental restriction on behavioural and physiological responses of pre-parturient pigs. Applied Animal Behaviour Science 71, 203-216.

7.   Op cit., note 2.

8.   Lawrence, A.B. and Terlouw, E.M.C. (1993)  A review of behavioral factors involved in the development and continued performance of stereotypic behaviors in pigs.  Journal of Animal Science 71, 2815-2825.

9.   Weng, R.C., Edwards, S.A. and English, P.R. (1998)  Behaviour, social interactions and lesion scores of group-housed sows in relation to floor space allowance.  Applied Animal Behaviour Science 59, 307-316.

10.   Op cit., note 7.

11.   Hemsworth, P.H. (2000)  The human factor:  influence on livestock performance and welfare. Proceedings of the New Zealand Society of Animal Production 60, 237-240.

12.   Gregory, N.G. and Devine, C.D.  (1999)  Survey of sow accommodation systems used in New Zealand. New Zealand Journal of Agricultural Research 42, 187-194

13.   Op cit., note 2.

14.   CWF (Compassion in World Farming Trust) (2000)  The welfare of Europe’s sows in close confinement stalls.  A report prepared for the European Coalition for Farm Animals, 35pp.