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Stephanie Torrey

Position/Title: Senior Research Associate
Phone: (519) 824-4120 ext. 53660
Office: ANNU 255

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As an associate graduate faculty member and research scientist, Stephanie Torrey studies poultry behaviour and welfare, focusing on meat-producing birds such as broiler chickens, broiler breeders and turkeys. She spent nine years working as a research scientist for Agriculture and Agrifood Canada, where she studied swine before she transferred to poultry research at the University of Guelph. Studying poultry behaviour and welfare offers a variety of research opportunities that have direct applications for producers. Stephanie enjoys collaborating on research projects with graduate students, departmental colleagues and external partners.   

Academic History

  • B.S. in Biology, Worcester Polytechnic Institute (1997)
  • M.S. in Animal Science, Purdue University (2001)
  • Ph.D. in Animal Science, University of Guelph (2005)

Affiliations and Partnerships

  • Campbell Centre for the Study of Animal Welfare
  • International Society for Applied Ethology
  • Poultry Health Research Network
  • Poultry Science Association
  • World’s Poultry Science Association 

Research Impact

With more than 15 years of research experience in farm animal behaviour and welfare, Stephanie is using her expertise to improve animal welfare and strengthen the Canadian poultry industry. Her research has explored a range of factors that affect poultry welfare, including behaviour, nutrition, genetics and management. Working with government partners and scientists’ committees, her research has led to improved production guidelines for farm animals, including poultry and swine. 

Current Research Projects

Feed restriction practices in broiler breeders

One of Stephanie’s research areas focuses on alternative feeding strategies for broiler breeders to reduce welfare problems associated with rapid growth and necessary feed restriction. Broiler chickens are genetically selected for fast growth, and their parents (broiler breeders) have similar genetic potential. With their much longer production period, broiler breeders would become obese and develop obesity-related welfare and productivity problems if allowed to grow at the same rate as broilers. To help prevent these problems, their growth rate is limited through feed restriction practices, which contribute to a state of chronic hunger. Stephanie is examining nutritional and management factors that can be manipulated to reduce hunger experienced by breeders without negatively impacting their welfare and production. This project is funded by NSERC-CRD, OMAFRA, CHEP, OBHECC and Canadian Poultry Research Council.

 On-farm euthanasia for chickens and turkeys

A key research focus for Stephanie is evaluating humane methods of euthanasia for chickens, breeders, layers and turkeys on farms. When poultry become sick, injured or unprofitable, farmers need an effective and humane method to cull birds. Through this project, Stephanie and her team are examining both physical and gaseous methods of euthanasia to provide humane options to poultry producers. This project is funded by NSERC-CRD, OMAFRA, LRIC-PIC, Canadian Poultry Research Council, Egg Farmers of Canada and Chicken Farmers of Saskatchewan.

Development of injurious pecking in turkeys

Stephanie is also studying injurious pecking behaviour in commercially-raised turkeys. Pecking is a problematic behaviour that often occurs in male turkeys that are bred for their large size. As they reach sexual maturity, male turkeys become more aggressive and fight for dominance. Producers can experience huge losses if pecking behaviour is not controlled, as birds often need to be culled or their carcasses are downgraded at processing. This project is funded by LRIC-PIC, Canadian Poultry Research Council and Hybrid Turkeys.

Evaluating slow-growing strains of broiler chickens

 A new research focus for Stephanie involves studying alternative strains of broiler chickens to assess their welfare and production. In response to welfare concerns related to broiler chickens’ fast growth rates, there is increasing demand among food retailers, restaurants and consumers for meat from slower growing strains of broiler chickens. Yet, little is known about the welfare of these broilers and how their behaviour, physiology, nutrient utilization, carcass quality and meat quality compare to traditional strains, particularly when raised without the use of antibiotics. Funding for this project is provided by GAP and U of G’s Food from Thought Canada First Research Excellence Fund research initiative.

Graduate Student Information

Graduate students working with Stephanie have the opportunity to gain hands-on experience in research projects with industry, and federal and provincial partners. The projects are collaborative and multidisciplinary, involving aspects of behaviour, welfare, nutrition, health, genetics and production. Her graduate and undergraduate students have worked on projects that improve the welfare of pigs and poultry. Stephanie sees herself as a coach who encourages her students to pursue their own research interests from a big-picture perspective. She invites students with strong communication skills, experience writing for scientific publications and on-farm experience to contact her. **Summer/Fall 2019, there are no available graduate student/post doc positions in the Torrey lab at this time**

Featured Publications

Bandara, R.M.A.S., S. Torrey, P.V. Turner, A. zur Linden, A. Bolinder, K. Schwean-Lardner and T.M. Widowski. 2019. Efficacy of a novel mechanical cervical dislocation device in comparison to manual cervical dislocation in layer chickens. Animals. 9(7), 407;

Arrazola, A. and S. Torrey. 2019. Conditioned place avoidance using capsuled calcium propionate as an appetite suppressant for broiler breeders. PLoS One. 14(7): e0206271. https://doi. org/10.1371/journal.pone.0206271

Arrazola, A. and S. Torrey. 2019. The development of fault bars in domestic chickens (Gallus gallus domesticus) is affected by acute stressors. Anim. Welf. 28(3):279-286.

Hernandez, E., F. James, S. Torrey, K. Schwean-Lardner, G. Monteith, T. Widowski and P.V. Turner. 2019. Electroencephalographic, physiologic and behavioural responses during cervical dislocation euthanasia in turkeys. BMC Veterinary Research. 15(1):132.

Bandara, R.M.A.S., S. Torrey, P.V. Turner, K. Schwean-Lardner and T.M. Widowski. 2019. Anatomical pathology, and behavioural and physiological responses induced by application of non-penetrating captive bolt devices in layer chickens. Front. Vet Sci. Anim. Behav. Welfare. doi: 10.3389/fvets.2019.00089

Arrazola, A., E. Mosco, T.M. Widowski, M.T. Guerin, E.G. Kiarie and S. Torrey. 2019. The Effect of Alternative Feeding Strategies for Broiler Breeder Pullets: 1. Welfare and Performance during Rearing. Poult. Sci. doi: 10.3382/ps/pez17043.  

Roehrig, C. and S. Torrey. 2019. Mortality and early feeding behavior of female turkey poults during the first week of life. Front. Vet Sci. Anim. Behav. Welfare.

Baker, B.I., S. Torrey, T.M. Widowski, P.V. Turner, T.D. Knezacek, T.G. Crowe and K. Schwean-Lardner. 2019. Evaluation of carbon dioxide induction methods for the euthanasia of day-old cull broiler chicks. Poult. Sci.  98(5): 2043–2053

Woolcott, C.R., S. Torrey, P.V. Turner, H. Chalmers, L. Levison, K. Schwean-Lardner and T.M. Widowski. 2018. Assessing a Method of Mechanical Cervical Dislocation as a Humane Option for On-Farm Killing using Anesthetized Poults and Young Turkey. Front. Vet Sci. Anim. Behav. Welfare

Dalton, H.A., B.J. Wood, T.M. Widowski, M.T. Guerin and S. Torrey. 2018. Comparing the behavioural organization of head pecking, severe feather pecking, and gentle feather pecking in domestic turkeys. Appl. Anim. Behav. Sci. 204:66-71.

Woolcott, C.R., S. Torrey, P.V. Turner, L. Serpa, K. Schwean-Lardner and T.M. Widowski. 2018. Evaluation of Two Models of Non-Penetrating Captive Bolt Devices for On-Farm Euthanasia of Turkeys. Animals. 8(3), 42; doi:10.3390/ani8030042

Leung, H., A. Arrazola, S. Torrey and E. Kiarie. 2018. Utilization of soy hulls, oat hulls and flax meal fiber in adult broiler breeder hens. Poult. Sci.