Register      Login
Animal Production Science Animal Production Science Society
Food, fibre and pharmaceuticals from animals
RESEARCH ARTICLE

Key determinants of pig welfare: implications of animal management and housing design on livestock welfare

P. H. Hemsworth
+ Author Affiliations
- Author Affiliations

Animal Welfare Science Centre, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Vic. 3010, Australia. Email: phh@unimelb.edu.au

Animal Production Science 58(8) 1375-1386 https://doi.org/10.1071/AN17897
Submitted: 25 December 2017  Accepted: 11 April 2018   Published: 7 May 2018

Abstract

The present review using the pig as a model has highlighted the importance of the design of the housing system on the welfare of farm animals. It has emphasised the need for research on animal welfare in new and modified housing systems, as well as current but contentious systems, to be attentive to the design contributions of these systems to animal welfare. The review has highlighted areas for future research to safeguard sow and piglet welfare, including the following: effective environmental enrichment for gestating sows in intensive, indoor and non-bedded systems; opportunities to increase foraging and feeding times in feed-restricted gestating sows; design features that allow both access to important resources, such as feed, water and a comfortable lying area, and escape opportunities to reduce aggression and minimise risks to the welfare of group-housed sows; and less confined farrowing and lactation systems. The review also shows that animal welfare problems may be less a function of the type of housing system than of how well it operates. The skills, knowledge and motivation of stockpeople to effectively care for and manage their animals are integral to the standard of welfare experienced by their animals. Attitudes influence not only the manner in which stockpeople handle animals, but also their motivation to care for their animals. Thus, training targeting technical skills and knowledge as well as the attitudes and behaviours of stockpeople should be a primary component of the human resource management practices at a farm. While public concerns and policy debates often focus on intensive housing systems, research indicates that the design and management of both indoor and outdoor housing systems is probably more important for animal welfare than is generally recognised.

Additional keywords: intensive housing, public concerns, welfare risks.


References

Abou-Ismail UA, Mendl MT (2016) The effects of enrichment novelty versus complexity in cages of group-housed rats (Rattus norvegicus). Applied Animal Behaviour Science 180, 130–139.
The effects of enrichment novelty versus complexity in cages of group-housed rats (Rattus norvegicus).Crossref | GoogleScholarGoogle Scholar |

Abou-Ismail UA, Burman OHB, Nicol CJ, Mendl M (2010) Effects of enhancing cage complexity on the behaviour and welfare of laboratory rats. Behavioural Processes 85, 172–180.
Effects of enhancing cage complexity on the behaviour and welfare of laboratory rats.Crossref | GoogleScholarGoogle Scholar |

Andersen IL, Bøe KE, Kristiansen AL (1999) The influence of different feeding arrangements and food type on competition at feeding in pregnant sows. Applied Animal Behaviour Science 65, 91–104.
The influence of different feeding arrangements and food type on competition at feeding in pregnant sows.Crossref | GoogleScholarGoogle Scholar |

Andersen IL, Berg S, Bøe KE (2005) Crushing of piglets by the mother sow (Sus scrofa): purely accidental or a poor mother? Applied Animal Behaviour Science 93, 229–243.
Crushing of piglets by the mother sow (Sus scrofa): purely accidental or a poor mother?Crossref | GoogleScholarGoogle Scholar |

Anil L, Anil SS, Deen J, Baidoo SK, Walker RD (2006) Effect of group size and structure on the welfare and performance of pregnant sows in pens with electronic sow feeders. Canadian Journal of Veterinary Research 70, 128–136.

Appleby MC, Lawrence AB (1987) Food restriction as a cause of stereotypic behaviour in tethered gilts. Animal Production 45, 103–110.
Food restriction as a cause of stereotypic behaviour in tethered gilts.Crossref | GoogleScholarGoogle Scholar |

Arey DS, Edwards SA (1998) Factors affecting aggression between sows after mixing and the consequences for welfare and production. Livestock Production Science 56, 61–70.
Factors affecting aggression between sows after mixing and the consequences for welfare and production.Crossref | GoogleScholarGoogle Scholar |

Barnett JL (1997) Modifying the design of group pens with individual feeding places affects the welfare of pigs. In ‘Proceedings of the 5th international symposium of the American Society of Agricultural Engineers’. (Eds RW Bottcher, SJ Hoff) pp. 613–618. (American Society of Agricultural Engineers: St Joseph, MI)

Barnett JL, Hemsworth PH, Cronin GM, Newman EA, McCallum TH, Chilton D (1992) Effects of pen size, partial stalls and method of feeding on welfare-related behavioural and physiological responses of group-housed pigs. Applied Animal Behaviour Science 34, 207–220.
Effects of pen size, partial stalls and method of feeding on welfare-related behavioural and physiological responses of group-housed pigs.Crossref | GoogleScholarGoogle Scholar |

Barnett JL, Hemsworth PH, Cronin GM, Jongman EC, Hutson GD (2001) A review of the welfare issues for sows and piglets in relation to housing. Australian Journal of Agricultural Research 52, 1–28.
A review of the welfare issues for sows and piglets in relation to housing.Crossref | GoogleScholarGoogle Scholar |

Baxter EM, Lawrence AB, Edwards SA (2012) Alternative farrowing accommodation: welfare and economic aspects of existing farrowing and lactation systems for pigs. Animal 6, 96–117.
Alternative farrowing accommodation: welfare and economic aspects of existing farrowing and lactation systems for pigs.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC38votlGmtQ%3D%3D&md5=b73cfb40815815262c1959cf0f6d2fe1CAS |

Bench CJ, Rioja-Lang FC, Hayne SM, Gonyou HW (2013a) Group gestation housing with individual feeding – I: how feeding regime, resource allocation, and genetic factors affect sow welfare. Livestock Science 152, 208–217.
Group gestation housing with individual feeding – I: how feeding regime, resource allocation, and genetic factors affect sow welfare.Crossref | GoogleScholarGoogle Scholar |

Bench CJ, Rioja-Lang FC, Hayne SM, Gonyou HW (2013b) Group gestation housing with individual feeding – II: how space allowance, group size and composition, and flooring affect sow welfare. Livestock Science 152, 218–227.
Group gestation housing with individual feeding – II: how space allowance, group size and composition, and flooring affect sow welfare.Crossref | GoogleScholarGoogle Scholar |

Bergeron R, Gonyou HW (1997) Effects of increasing energy intake and foraging behaviours on the development of stereotypies in pregnant sows. Applied Animal Behaviour Science 53, 259–270.
Effects of increasing energy intake and foraging behaviours on the development of stereotypies in pregnant sows.Crossref | GoogleScholarGoogle Scholar |

Bergeron R, Bolduc J, Ramonet Y, Meunier-Salaün MC, Robert S (2000) Feeding motivation and stereotypies in pregnant sows fed increasing levels of fibre and/or food. Applied Animal Behaviour Science 70, 27–40.
Feeding motivation and stereotypies in pregnant sows fed increasing levels of fibre and/or food.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC2sbivFKltw%3D%3D&md5=3d706de614e9629600f1100a7915eb9eCAS |

Bergeron R, Badnell-Waters AJ, Lambton S, Mason G (2006) Stereotypic oral behaviour in captive ungulates: foraging, diet and gastrointestinal function. In ‘Stereotypic animal behaviour. Fundamentals and applications to welfare’. 2nd edn. (Eds G Mason, J Rushen) pp. 19–27. (CABI Publishing: Wallingford, UK)

Boissy A, Manteuffel G, Jensen MB, Oppermann M, Spruijt B, Keeling LJ, Winckler C, Forkman B, Dimitrov I, Langbein J, Bakken M, Veissier I, Aubert A (2007) Assessment of positive emotions in animals to improve their welfare. Physiology & Behavior 92, 375–397.
Assessment of positive emotions in animals to improve their welfare.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXhtF2htr7K&md5=f5e1ae611d3a6ec738ef0a153e60f8adCAS |

Brouns F, Edwards SA, English PR (1994) Effect of dietary fibre and feeding system on activity and oral behaviour of group housed gilts. Applied Animal Behaviour Science 39, 215–223.
Effect of dietary fibre and feeding system on activity and oral behaviour of group housed gilts.Crossref | GoogleScholarGoogle Scholar |

Coleman GJ, Hemsworth PH (2014) Training to improve stockperson beliefs and behaviour towards livestock enhances welfare and productivity. Scientific and Technical Review of the Office International des Epizooties 33, 131–137.
Training to improve stockperson beliefs and behaviour towards livestock enhances welfare and productivity.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC2cbgt1Smuw%3D%3D&md5=6ac01a3378789d7002dc909a0bc24303CAS |

Coleman GJ, Hemsworth PH, Hay M, Cox M (1998) Predicting stockperson behaviour towards pigs from attitudinal and job-related variables and empathy. Applied Animal Behaviour Science 58, 63–75.
Predicting stockperson behaviour towards pigs from attitudinal and job-related variables and empathy.Crossref | GoogleScholarGoogle Scholar |

Coleman GJ, Hemsworth PH, Hay M, Cox M (2000) Modifying stockperson attitudes and behaviour towards pigs at a large commercial farm. Applied Animal Behaviour Science 66, 11–20.

Coleman GJ, McGregor M, Hemsworth PH, Boyce J, Dowling S (2003) The relationship between beliefs, attitudes and observed behaviours of abattoir personnel in the pig industry. Applied Animal Behaviour Science 82, 189–200.
The relationship between beliefs, attitudes and observed behaviours of abattoir personnel in the pig industry.Crossref | GoogleScholarGoogle Scholar |

Coleman GJ, Rice M, Hemsworth PH (2012) Human-animal relationships at sheep and cattle abattoirs. Animal Welfare 21, 15–21.
Human-animal relationships at sheep and cattle abattoirs.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XotVymt70%3D&md5=c8defc9255ec0c8d802e50e333e5349fCAS |

Condous PC, Plush KJ, Tilbrook AJ, van Wettere WHEJ (2016) Reducing sow confinement during farrowing and in early lactation increases piglet mortality. Journal of Animal Science 94, 3022–3029.

Cronin GM, Smith JA (1992) Suckling behaviour of sows in farrowing crates and straw-bedded pens. Applied Animal Behaviour Science 33, 175–189.
Suckling behaviour of sows in farrowing crates and straw-bedded pens.Crossref | GoogleScholarGoogle Scholar |

Cronin GM, Barnett JL, Hodge FM, Smith JA, McCallum TH (1991) The welfare of pigs in two farrowing/lactation environments: cortisol responses of sows. Applied Animal Behaviour Science 32, 117–127.
The welfare of pigs in two farrowing/lactation environments: cortisol responses of sows.Crossref | GoogleScholarGoogle Scholar |

Cronin GM, Simpson GJ, Hemsworth PH (1996) The effects of the gestation and farrowing environments on sow and piglet behaviour and piglet survival and growth in early lactation. Applied Animal Behaviour Science 46, 175–192.
The effects of the gestation and farrowing environments on sow and piglet behaviour and piglet survival and growth in early lactation.Crossref | GoogleScholarGoogle Scholar |

Cronin GM, Rault J-L, Glatz PC (2014) Lessons learned from past experience with intensive livestock management systems. Scientific and Technical Review of the Office International des Epizooties 33, 139–151.
Lessons learned from past experience with intensive livestock management systems.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC2cbgt1Slsg%3D%3D&md5=b39ab59bbfac36696785321776b29bc9CAS |

De Jong IC, Ekkel ED, Van de Burgwal JA, Lambooij E, Korte SM, Ruis MAW, Moolhaas JM, Blokhuis HJ (1998) Effects of straw-bedding on physiological responses and behaviour in growing pigs. Physiology & Behavior 64, 303–310.

De Jong IC, Prelle IT, Van de Burgwal JA, Lambooij E, Korte SM, Blokhuis HJ, Koolhaas JM (2000) Effects of environmental enrichment on behavioral responses to novelty, learning, and memory, and the circadian rhythm in cortisol in growing pigs. Physiology & Behavior 68, 571–578.

De Groot J, De Jong IC, Prelle IT, Koolhaas JM (2000) Immunity in barren and enriched housed pigs differing in baseline cortisol concentration. Physiology & Behavior 71, 217–223.

Estep DQ, Hetts S (1992) Interactions, relationships, and bonds: the conceptual basis for scientist–animal relations. In ‘The inevitable bond: examining scientist–animal interactions’. (Eds H Davis, AD Balfour) pp. 6–26. (Cambridge University Press: Cambridge, UK)

European Commission Directive (2001) Commission Directive 2001/93/EC of 9 November 2001 amending Directive 91/630/EEC laying down minimum standards for the protection of pigs. Official Journal L 316, 1/12/2001, P. 0036-0038.

Fraser D (2005) ‘Animal welfare and the intensification of animal production. An alternative interpretation.’ FAO readings in ethics, 2. (FAO: Rome)

Fraser D (2008) ‘Understanding animal welfare: the science in its cultural context.’ (Wiley–Blackwell: Chichester, UK)

Hales J, Moustsen VA, Nielsen MBF, Hansen CF (2015) Temporary confinement of loose housed hyper-prolific sows reduces piglet mortality. Journal of Animal Science 93, 4079–4088.
Temporary confinement of loose housed hyper-prolific sows reduces piglet mortality.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC2MXhsVGksrrF&md5=92ca6cb6d13f3d4fb31fee37677ad949CAS |

Hales Pedersen J (2015) Loose housing or temporary confinement of sows in designed farrowing pens. PhD Thesis, University of Copenhagen, Copenhagen, Denmark.

Hemsworth PH (2018) Defining and ensuring animal welfare in pig production: an overview. In ‘Achieving sustainable production of pig meat. Volume 3: animal health and welfare’. (Ed. J Wiseman) pp. 125–150. (Burleigh Dodds Scientific Publishing: Cambridge, UK)

Hemsworth PH, Boivin X (2011) Human contact. In ‘Animal welfare’. (Eds MC Appleby, JA Mench, IAS Olsson, BO Hughes) pp. 246–262. (CABI Publishing: Wallingford, UK)

Hemsworth PH, Coleman GJ (2009) Animal welfare and management. In ‘Food safety assurance and veterinary public health. Vol. 5. Welfare productions animals: assessment and management risks’. (Eds FJM Smulders, B Algers) pp. 133–147. (Wageningen Academic Publishers: Wageningen, Netherlands)

Hemsworth PH, Coleman GJ (2011) ‘Human–livestock interactions: the stockperson and the productivity and welfare of intensively-farmed animals’, 2nd edn. (CAB International: Wallingford, UK)

Hemsworth PH, Coleman GJ (2016) ‘Addressing ethical dilemmas in producing food and fibre: achieving a well-informed community and rational discussions.’ (Australian Government Productivity Commission Submission – Regulation of Australian Agriculture, Commonwealth of Australia 2016). Available at https://www.pc.gov.au/__data/assets/pdf_file/0020/200369/sub087-agriculture.pdf [Verified 10 January 2018]

Hemsworth PH, Barnett JL, Hansen C, Winfield CG (1986) Effects of social environment on welfare status and sexual behaviour of female pigs. II. Effects of space allowance. Applied Animal Behaviour Science 16, 259–267.
Effects of social environment on welfare status and sexual behaviour of female pigs. II. Effects of space allowance.Crossref | GoogleScholarGoogle Scholar |

Hemsworth PH, Coleman GJ, Barnett JL (1994) Improving the attitude and behaviour of stockpeople towards pigs and the consequences on the behaviour and reproductive performance of commercial pigs. Applied Animal Behaviour Science 39, 349–362.

Hemsworth PH, Coleman GJ, Barnett JL, Borg S, Dowling S (2002) The effects of cognitive behavioral intervention on the attitude and behavior of stockpersons and the behavior and productivity of commercial dairy cows. Journal of Animal Science 80, 68–78.

Hemsworth PH, Rice M, Karlen MG, Calleja L, Barnett JL, Nash J, Coleman GJ (2011) Human–animal interactions at abattoirs: relationships between handling and animal stress in sheep and cattle. Applied Animal Behaviour Science 135, 24–33.
Human–animal interactions at abattoirs: relationships between handling and animal stress in sheep and cattle.Crossref | GoogleScholarGoogle Scholar |

Hemsworth PH, Rice M, Nash J, Giri K, Butler KL, Tilbrook AJ, Morrison RS (2013) Effects of group size and floor space allowance on grouped sows: aggression, stress, skin injuries and reproductive performance. Journal of Animal Science 91, 4953–4964.
Effects of group size and floor space allowance on grouped sows: aggression, stress, skin injuries and reproductive performance.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3sXhs1SqtLnM&md5=b3d5aaddc7a159f8d5c33abb93ee7a8fCAS |

Hemsworth PH, Mellor DJ, Cronin GM, Tilbrook AJ (2015) Scientific assessment of animal welfare. New Zealand Veterinary Journal 63, 24–30.
Scientific assessment of animal welfare.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC2M7lt1Cntg%3D%3D&md5=36bacca1f33c1905da680baf5ce86136CAS |

Hemsworth PH, Morrison RS, Tilbrook AJ, Butler KL, Rice M, Moeller S (2016a) Effects of varying floor space on aggressive behavior and cortisol concentrations in group housed sows. Journal of Animal Science 94, 4809–4818.
Effects of varying floor space on aggressive behavior and cortisol concentrations in group housed sows.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC2sXitlWgtro%3D&md5=77828d98b6f6b09a01287cf6b7e7feccCAS |

Hemsworth PH, Rice M, Borg S, Edwards LE, Ponnampalam EN, Coleman GJ (2016b) Relationship between handling, behaviour and stress in lambs at abattoirs. In ‘Proceedings of 31st biennial conference of the Australasian Society of Animal Production’, p. 79.

Hemsworth LM, Rault J-L, Hemsworth PH (2017) Sham chewing and sow welfare and productivity. Final report for the Co-operative Research Centre for High Integrity Australian Pork, 1C–118, September 2017.

Hemsworth PH, Sherwen SI, Coleman GJ (2018) Human contact In ‘Animal welfare’. 3rd edn. (Eds MC Appleby, IAS Olsson, F Galindo) pp. 294–314. (CABI Publishing: Wallingford, UK)

Hodges J (2000) Why livestock, ethics and quality of life? In ‘Livestock, ethics and quality of life’. (Eds J Hodges, IK Han) pp. 1–26. (CABI Publishing: Wallingford, UK)

Hutson GD (1991) A note on hunger in the pig: sows on restricted rations will sustain an energy deficit to gain additional food. Animal Production 52, 233–235.
A note on hunger in the pig: sows on restricted rations will sustain an energy deficit to gain additional food.Crossref | GoogleScholarGoogle Scholar |

Jarvis S, Lawrence AB, McLean KA, Chirnside J, Deans LA, Calvert SK (1998) The effect of environment on plasma cortisol and beta-endorphin in the parturient pig and the involvement of endogenous opioids. Animal Reproduction Science 52, 139–151.
The effect of environment on plasma cortisol and beta-endorphin in the parturient pig and the involvement of endogenous opioids.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1cXls1ynuro%3D&md5=784ec320aea4df2af0a4cc45c43f03eeCAS |

Jarvis S, Calvert SK, Stevenson J, van Leeuwen N, Lawrence AB (2002) Pituitary–adrenal activation in pre-parturient pigs (Sus scrofa) is associated with behavioural restriction due to lack of space rather than nesting substrate. Animal Welfare 11, 371–384.

Johnson AK, Marchant-Forde JN (2009) Welfare of pigs in the farrowing environment. In ‘The welfare of pigs’. (Ed. JN Marchant-Forde) pp. 141–88. (Springer Science and Business Media: New York)

Jones RB, Waddington D (1992) Modification of fear in domestic chicks, Gallus gallus domesticus via regular handling and early environmental enrichment. Animal Behaviour 43, 1021–1033.
Modification of fear in domestic chicks, Gallus gallus domesticus via regular handling and early environmental enrichment.Crossref | GoogleScholarGoogle Scholar |

KilBride AL, Mendl M, Statham P, Held S, Harris M, Cooper S, Green LE (2012) A cohort study of preweaning piglet mortality and farrowing accommodation on 112 commercial pig farms in England. Preventive Veterinary Medicine 104, 281–291.
A cohort study of preweaning piglet mortality and farrowing accommodation on 112 commercial pig farms in England.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC38zptlanuw%3D%3D&md5=e9b309019519e73a32a5a4ae8d29220cCAS |

Knox R, Salak-Johnson J, Hopgood M, Greiner L, Connor J (2014) Effect of day of mixing gestating sows on measures of reproductive performance and animal welfare. Journal of Animal Science 92, 1698–1707.
Effect of day of mixing gestating sows on measures of reproductive performance and animal welfare.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC2crmvVGgsw%3D%3D&md5=5f366e46261284c05021d89c513a2a3fCAS |

Langendijk P, Soede NM, Kemp B (2000) Effects of boar contact and housing conditions on estrus expression in weaned sows. Journal of Animal Science 78, 871–878.

Lawrence AB, Terlouw EMC (1993) A review of behavioural factors involved in the development and continued performance of stereotypic behaviours in pigs. Journal of Animal Science 71, 2815–2825.
A review of behavioural factors involved in the development and continued performance of stereotypic behaviours in pigs.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DyaK2c%2Fkt1GmtQ%3D%3D&md5=dc7a9349701fb086f2ed1820d9b8108bCAS |

Lawrence AB, Petherick JC, McLean KA, Deans LA, Chirnside J, Vaughan A, Clutton E, Terlouw EMC (1994) The effect of environment on behaviour, plasma cortisol and prolactin in parturient sows. Applied Animal Behaviour Science 39, 313–330.
The effect of environment on behaviour, plasma cortisol and prolactin in parturient sows.Crossref | GoogleScholarGoogle Scholar |

Lehmann ML, Herkenham M (2011) Environmental enrichment confers stress resiliency to social defeat through an infralimbic cortex-dependent neuroanatomical pathway. The Journal of Neuroscience 31, 6159–6173.
Environmental enrichment confers stress resiliency to social defeat through an infralimbic cortex-dependent neuroanatomical pathway.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXlsFSqsbg%3D&md5=6e70b72dcd31dada219386e0c2695209CAS |

Li YZ, Gonyou HW (2013) Comparison of management options for sows kept in pens with electronic feeding stations. Canadian Journal of Animal Science 93, 445–452.
Comparison of management options for sows kept in pens with electronic feeding stations.Crossref | GoogleScholarGoogle Scholar |

Li Y, Wang L (2011) Effects of previous housing system on agonistic behaviors of growing pigs at mixing. Applied Animal Behaviour Science 132, 20–26.
Effects of previous housing system on agonistic behaviors of growing pigs at mixing.Crossref | GoogleScholarGoogle Scholar |

Marchant-Forde JN (2009) Future perspectives of the welfare of pigs. In ‘The welfare of pigs’. (Ed. JN Marchant-Forde) pp. 331–342. (Springer Science and Business Media: New York)

Mason GJ (1991) Stereotypies: a critical review. Animal Behaviour 41, 1015–1037.

Mason G (2006) Stereotypic behaviour in captive animals: fundamentals and implications for welfare and beyond. In ‘Stereotypic animal behaviour: fundamentals and applications to welfare’. (Ed. G Mason, J Rushen) pp. 325–357. (CABI Publishing: Wallingford, UK)

Mason GJ, Latham NR (2004) Can’t stop, won’t stop: is stereotypy a reliable animal welfare indicator? Animal Welfare 13, S57–S69.

Mellor DJ (2012) Animal emotions, behaviour and the promotion of positive welfare states. New Zealand Veterinary Journal 60, 1–8.
Animal emotions, behaviour and the promotion of positive welfare states.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC38%2Fot1Wgug%3D%3D&md5=c08377c20b008f85802fd24506a17e10CAS |

Mellor DJ, Patterson-Kane E, Stafford KJ (2009) ‘The sciences of animal welfare’. (Wiley–Blackwell Publishing: Oxford, UK)

Meunier-Salaün MC, Edwards SA, Robert S (2001) Effect of dietary fibre on the behaviour and health of the restricted sow. Animal Feed Science and Technology 90, 53–69.
Effect of dietary fibre on the behaviour and health of the restricted sow.Crossref | GoogleScholarGoogle Scholar |

Morrison RM, Cronin GM, Hemsworth PH (2011) Sow housing in Australia: current Australian welfare research and future directions. In ‘Manipulating pig production XIII. Proceedings of the 13th biennial conference of the Australasian Pig Science Association’. pp. 219–238.

Moustsen VA, Hales J, Lahrmann HP, Weber PM, Hansen CF (2013) Confinement of lactating sows in crates for 4 days after farrowing reduces piglet mortalities. Animal 7, 648–654.
Confinement of lactating sows in crates for 4 days after farrowing reduces piglet mortalities.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC3s7nt1ahsA%3D%3D&md5=6ff0eff38f6960e9b063734f8f5c9001CAS |

Newberry RC (1995) Environmental enrichment: increasing the biological relevance of captive environments. Applied Animal Behaviour Science 44, 229–243.
Environmental enrichment: increasing the biological relevance of captive environments.Crossref | GoogleScholarGoogle Scholar |

Oliviero C, Heinonen M, Valros A, Halli O, Peltoniemi OAT (2008) Effect of the environment on the physiology of the sow during late pregnancy, farrowing and early lactation. Animal Reproduction Science 105, 365–377.
Effect of the environment on the physiology of the sow during late pregnancy, farrowing and early lactation.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD1c7mslSgug%3D%3D&md5=e355e0f6edb2787cf417eae01aee1addCAS |

Oostindjer M, van den Brand H, Kemp B, Bolhuis J (2011) Effects of environmental enrichment and loose housing of lactating sows on piglet behaviour before and after weaning. Applied Animal Behaviour Science 134, 31–41.
Effects of environmental enrichment and loose housing of lactating sows on piglet behaviour before and after weaning.Crossref | GoogleScholarGoogle Scholar |

Pedersen LJ, Rojkittikhun T, Einarsson D, Edqvist LE (1993) Postweaning grouped sows: effects of aggression on hormonal patterns and estrus behaviour. Applied Animal Behaviour Science 38, 25–39.
Postweaning grouped sows: effects of aggression on hormonal patterns and estrus behaviour.Crossref | GoogleScholarGoogle Scholar |

Pedersen L, Heiskanen JT, Damm BI (2003) Sexual motivation in relation to social rank in pair-housed sows. Animal Reproduction Science 75, 39–53.
Sexual motivation in relation to social rank in pair-housed sows.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD3s%2FislOnsQ%3D%3D&md5=8351965b6150b58baa288c6db88782fbCAS |

Ramonet Y, Meunier-Salaun MC, Dourmad JY (1999) High-fiber diets in pregnant sows: digestive utilization and effects on the behavior of the animals. Journal of Animal Science 77, 591–599.
High-fiber diets in pregnant sows: digestive utilization and effects on the behavior of the animals.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1MXjs1ersr4%3D&md5=d1ee9af9a1657643405f0a0e3a33ccc8CAS |

Rault J-L, Morrison RM, Hansen C, Hemsworth PH (2014) Effects of group housing after weaning on sow welfare and sexual behavior. Journal of Animal Science 92, 5683–5692.
Effects of group housing after weaning on sow welfare and sexual behavior.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC2MXhtV2gsr0%3D&md5=d4a4170621fb9fcc72aa05bea0ddfc08CAS |

Remience V, Wavreille J, Canart BV, Meunier-Salaün MC, Prunier A, Bartiaux-Thill N, Nicks B, Vandenheede M (2008) Effects of space allowance on the welfare of dry sows kept in dynamic groups and fed with electronic sow feeder. Applied Animal Behaviour Science 112, 284–296.
Effects of space allowance on the welfare of dry sows kept in dynamic groups and fed with electronic sow feeder.Crossref | GoogleScholarGoogle Scholar |

Robert S, Matte JJ, Farmer C, Girard CL, Martineau GP (1993) High-fibre diets for sows: effects on stereotypies and adjunctive drinking. Applied Animal Behaviour Science 37, 297–309.
High-fibre diets for sows: effects on stereotypies and adjunctive drinking.Crossref | GoogleScholarGoogle Scholar |

Robert S, Rushen J, Farmer C (1997) Both energy content and bulk of feed affect stereotypic behaviour, heart rate and feeding motivation of female pigs. Applied Animal Behaviour Science 54, 161–171.
Both energy content and bulk of feed affect stereotypic behaviour, heart rate and feeding motivation of female pigs.Crossref | GoogleScholarGoogle Scholar |

Rushen J, de Passillé AMB (1992) The scientific assessment of the impact of housing on animal welfare: a critical review. Canadian Journal of Animal Science 72, 721–743.
The scientific assessment of the impact of housing on animal welfare: a critical review.Crossref | GoogleScholarGoogle Scholar |

Salak-Johnson JL, Niekamp SR, Rodriguez-Zas SL, Ellis M, Curtis SE (2007) Space allowance for dry, pregnant sows in pens: body condition, skin lesions and performance. Journal of Animal Science 85, 1758–1769.
Space allowance for dry, pregnant sows in pens: body condition, skin lesions and performance.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXntV2msb8%3D&md5=b7950b0375629868da08b1c10c00bc12CAS |

Samarakone TS, Gonyou HW (2009) Domestic pigs alter their social strategy in response to social group size. Applied Animal Behaviour Science 121, 8–15.
Domestic pigs alter their social strategy in response to social group size.Crossref | GoogleScholarGoogle Scholar |

Schouten W, Rushen J (1992) Effects of naloxone on stereotypic and normal behaviour of tethered and loose-housed sows. Applied Animal Behaviour Science 33, 17–26.

Sekiguchi T, Koketsu Y (2004) Behavior and reproductive performance by stalled breeding females on a commercial swine farm. Journal of Animal Science 82, 1482–1487.
Behavior and reproductive performance by stalled breeding females on a commercial swine farm.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXjs1Gqsr0%3D&md5=d37ef3ed6cf74d02089ff3983071d51aCAS |

Singh C, Verdon M, Cronin GM, Hemsworth PH (2017) The behaviour and welfare of sows and piglets in farrowing crates or lactation pens. Animal 11, 1210–1221.
The behaviour and welfare of sows and piglets in farrowing crates or lactation pens.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC2sXhtVSjtrbN&md5=5c186074a40396866c6ce55e368c02c9CAS |

Stevens BG, Karlen M, Morrison R, Gonyou HW, Butler KL, Kerswell KJ, Hemsworth PH (2015) Effects of stage of gestation at mixing on aggression, injuries and stress in sows. Applied Animal Behaviour Science 165, 40–46.
Effects of stage of gestation at mixing on aggression, injuries and stress in sows.Crossref | GoogleScholarGoogle Scholar |

Strawford ML, Li YZ, Gonyou HW (2008) The effect of management strategies and parity on the behaviour and physiology of gestating sows housed in an electronic sow feeding system. Canadian Journal of Animal Science 88, 559–567.
The effect of management strategies and parity on the behaviour and physiology of gestating sows housed in an electronic sow feeding system.Crossref | GoogleScholarGoogle Scholar |

Taylor IA, Barnett JL, Cronin GM (1997) Optimum group size for pigs. In ‘Proceedings of the 5th international symposium of the American Society of Agricultural Engineers’. (Eds RW Bottcher, SJ Hoff) pp. 965–971. (American Society of Agricultural Engineers: St Joseph, MI)

Te Velde HT, Aarts N, Van Woerkum C (2002) Dealing with ambivalence: farmers’ and consumers’ perceptions of animal welfare in livestock breeding. Journal of Agricultural & Environmental Ethics 15, 203–219.
Dealing with ambivalence: farmers’ and consumers’ perceptions of animal welfare in livestock breeding.Crossref | GoogleScholarGoogle Scholar |

Terlouw EM, Lawrence AB, Illius AW (1991) Influences of feeding level and physical restriction on development of stereotypies in sows. Animal Behaviour 42, 981–991.

Terlouw EMC, Lawrence AB (1993) Long-term effects of food allowance and housing on development of stereotypies in pigs. Applied Animal Behaviour Science 38, 103–126.
Long-term effects of food allowance and housing on development of stereotypies in pigs.Crossref | GoogleScholarGoogle Scholar |

Thodberg K, Jensen KH, Herskin MS (2002) Nursing behaviour, postpartum activity and reactivity in sows: effects of farrowing environment, previous experience and temperament. Applied Animal Behaviour Science 77, 53–76.
Nursing behaviour, postpartum activity and reactivity in sows: effects of farrowing environment, previous experience and temperament.Crossref | GoogleScholarGoogle Scholar |

Tilbrook AJ, Ralph CR (2017) Hormones, stress and the welfare of animals. Animal Production Science
Hormones, stress and the welfare of animals.Crossref | GoogleScholarGoogle Scholar |

Turner SP, Edwards SA, Bland VC (1999) The influence of drinker allocation and group size on the drinking behaviour, welfare and production of growing pigs. Animal Science 68, 617–624.
The influence of drinker allocation and group size on the drinking behaviour, welfare and production of growing pigs.Crossref | GoogleScholarGoogle Scholar |

Turner SP, Ewen M, Rooke JA, Edwards SA (2000) The effect of space allowance on performance, aggression and immune competence of growing pigs housed on straw deep-litter at different group sizes. Livestock Production Science 66, 47–55.
The effect of space allowance on performance, aggression and immune competence of growing pigs housed on straw deep-litter at different group sizes.Crossref | GoogleScholarGoogle Scholar |

Van de Weerd HA, Day JEL (2009) A review of environmental enrichment for pigs housed in intensive housing systems. Applied Animal Behaviour Science 116, 1–20.

Vanhonacker F, Verbeke W, Van Poucke E, Buis S, Tuyttens FAM (2009) Societal concern related to stocking density, pen size and group size in farm animal production. Livestock Science 123, 16–22.
Societal concern related to stocking density, pen size and group size in farm animal production.Crossref | GoogleScholarGoogle Scholar |

Vanhonacker F, Verbeke W, Van Poucke E, Pieniak Z, Nijs G, Tuyttens FAM (2012) The concept of farm animal welfare: citizen perceptions and stakeholder opinion in Flanders. Journal of Agricultural & Environmental Ethics 25, 79–101.
The concept of farm animal welfare: citizen perceptions and stakeholder opinion in Flanders.Crossref | GoogleScholarGoogle Scholar |

Verdon M, Hansen CF, Rault J-L, Jongman E, Hansen LU, Plush K, Hemsworth PH (2015) Effects of group-housing on sow welfare: a review. Journal of Animal Science 93, 1999–2017.
Effects of group-housing on sow welfare: a review.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC2MXhtVCkt7nO&md5=59e1f2cd267c70cf4aadd85472780b0aCAS |

Verdon M, Morrison RS, Hemsworth PH (2016) Rearing piglets in multi-litter group lactation systems: effects on piglet aggression and injuries post-weaning. Applied Animal Behaviour Science 183, 35–41.
Rearing piglets in multi-litter group lactation systems: effects on piglet aggression and injuries post-weaning.Crossref | GoogleScholarGoogle Scholar |

Vieuille-Thomas C, Le Pape G, Signoret JP (1995) Stereotypies in pregnant sows: indications of influence of the housing system on the patterns expressed by the animals. Applied Animal Behaviour Science 44, 19–27.
Stereotypies in pregnant sows: indications of influence of the housing system on the patterns expressed by the animals.Crossref | GoogleScholarGoogle Scholar |

Vosough Ahmadi B, Stott AW, Baxter EM, Lawrence AB, Edwards SA (2011) Animal welfare and economic optimisation of farrowing systems. Animal Welfare 20, 57–67.

Waiblinger S, Boivin X, Pedersen V, Tosi M-V, Janczak AM, Visser EK, Jones RB (2006) Assessing the human–animal relationship in farmed species: a critical review. Applied Animal Behaviour Science 101, 185–242.
Assessing the human–animal relationship in farmed species: a critical review.Crossref | GoogleScholarGoogle Scholar |

Wang LH, Li YZ (2016) Effect of continuous access to feeding stalls during mixing on behavior, welfare, and performance of group-housed gestating sows in different social ranks. Canadian Journal of Animal Science 96, 386–396.
Effect of continuous access to feeding stalls during mixing on behavior, welfare, and performance of group-housed gestating sows in different social ranks.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC2sXhsVKltrrN&md5=7fd5845c707b80e52d4c0bc76ba45ddcCAS |

Weber R, Keil NM, Fehr M, Horat R (2007) Piglet mortality on farms using farrowing systems with or without crates. Animal Welfare 16, 277–279.

Weng RC, Edwards SA, English PR (1998) Behaviour, social interactions and lesion score of group-housed sows in relation to floor space allowance. Applied Animal Behaviour Science 59, 307–316.
Behaviour, social interactions and lesion score of group-housed sows in relation to floor space allowance.Crossref | GoogleScholarGoogle Scholar |

Würbel H, Chapman R, Rutland C (1998) Effect of feed and environmental enrichment on development of stereotypic wire-gnawing in laboratory mice. Applied Animal Behaviour Science 60, 69–81.