Leonie Jacobs

Dr. Jacobs’ research focuses on the improvement of production animal welfare. Her interests include win-win situations where both animals and people from the industry can profit. Her appointment at VT includes research and extension work. Her research interests include:

 Focus 1: Avoid suffering and ensure humane treatment

One part of Dr. Jacobs’ program is to ensure that production animals receive humane treatment and experience no avoidable pain or suffering. This work is directly applicable to the animal industry focusing on short-term solutions.

• A collaborative study (2018-2020) is focused on euthanasia of heavy poultry, evaluating five different methods of euthanasia for broilers, broiler breeders (parent flock) and turkeys.
• Another study (2019-2022) focuses on piglet pain experience and alleviation during painful management procedures such as castration. This study is first of all, focused on finding practical, short-term solutions to the painful castration procedures. Secondly, an online survey is under development to evaluate industry workers’ ability to identify pain through piglet facial expressions.

Focus 2: Provide production animals a high-quality life; a life worth living

Good animal welfare is not just the avoidance of suffering, it also includes positive experiences and associated emotions, comparable to pleasure or happiness in humans.

• A current study (2019-2023) focuses on quantifying positive welfare status, with an emphasis on assessing positive emotional state (long-term mood) in broiler chickens. This study aims to identify biomarkers that can indicate an animal’s emotional valence (positive versus negative), that are dose-dependent (higher/lower quantities of the biomarker when the animal is in a more positive emotional state).
• A new study (2020-2023) is focused on providing pasture-based broiler chickens with their preferred outdoor range, including trees and plants that can provide a second source of income for poultry producers (silvopasture-system). 

Extension efforts

Dr. Jacobs’ recently co-founded the Poultry Extension Collaborative, focusing on collaborative efforts aimed at the poultry industry, together with faculty from other US universities.

More information can be found here: https://www.poultry-welfare-extension.com/

Research

1. Book chapter: Jacobs, L., and F. A. M. Tuyttens. 2020. Improving welfare in catching and transport of broiler chickens. In: Understanding the behaviour and improving the welfare of chickens (ed. Prof. Christine Nicol). Burleigh Dodds Science Publishing. Accepted.
2. Jacobs, L., M. E. Persia, N. Siman-Tov, J. McCoy, M. Ahmad, J. Lyman, and L. Good. 2019. Impact of Water Sanitation on Broiler Chicken Production and Welfare Parameters. Journal of Applied Poultry Research. https://doi.org/10.1016/j.japr.2019.10.013
3. Jacobs, L., G. Vezzoli, B. Beerda, and J. A. Mench. 2019. Northern fowl mite infestation affects the nocturnal behavior of laying hens. Applied Animal Behaviour Science. https://doi.org/10.1016/j.applanim.2019.04.007
4. Jacobs, L., Bourassa, D.V., Harris, C.E., and Buhr, R.J. 2019. Euthanasia: Manual versus Mechanical Cervical Dislocation for Broilers. Animals 9. https://doi.org/10.3390/ani9020047
5. Jacobs, L., E. Delezie, L. Duchateau, K. Goethals, B. Ampe, J. Buyse, F.A.M. Tuyttens. 2017. Impact of transportation duration on stress responses in day-old chicks from young and old breeders. Research in Veterinary Science 112:172–176  https://doi.org/10.1016/j.rvsc.2017.04.015
6. Jacobs, L., E. Delezie, L. Duchateau, K. Goethals, J. Buyse, F.A.M. Tuyttens. 2017. Fit for transport? Assessment of fitness of broiler chickens before transportation to slaughter. Animal Welfare 26:335-343. https://doi.org/10.7120/09627286.26.3.335
7. Jacobs, L., E. Delezie, L. Duchateau, K. Goethals, F.A.M. Tuyttens. 2017. Broiler chickens dead on arrival: associated risk factors and welfare indicators. Poultry Science 96:259-265. https://doi.org/10.3382/ps/pew353
8. Jacobs, L., E. Delezie, L. Duchateau, K. Goethals, F.A.M. Tuyttens. 2017. Impact of the separate pre-slaughter stages on broiler chicken welfare. Poultry Science 96:266-273. https://doi.org/10.3382/ps/pew361
9. Jacobs, L., E. Delezie, L. Duchateau, K. Goethals, B. Ampe, E. Lambrecht, X. Gellynck, F.A.M. Tuyttens. 2016. Effect of post-hatch transportation duration and parental age on broiler chicken quality, welfare and productivity. Poultry Science 95:1973-1979. https://doi.org/10.3382/ps/pew155
10. Tuyttens, F.A.M., S. de Graaf, J. Heerkens, L. Jacobs, E. Nalon, S. Ott, L. Stadig, E. Van laer, B. Ampe. 2014. Observer bias in animal behaviour research: can we believe what we score, if we score what we believe? Animal Behaviour 90:273-280. https://doi.org/10.1016/j.anbehav.2014.02.007

Extension

1. Poultry Extension Collaborative – monthly newsletter vol 1. https://www.poultry-welfare-extension.com/
2. Jacobs, L., D. V. Bourassa, C. E. Harris, and R. J. Buhr. 2019. Euthanasia for Broiler Chickens: Manual and Mechanical Cervical Dislocation Methods’, Virginia Cooperative Extension publication | Virginia Tech. https://www.pubs.ext.vt.edu/APSC/APSC-161/APSC-161.html
3. Jacobs, L. 2019. Welfare considerations for on-farm or backyard slaughter of poultry. Virginia Cooperative Extension publication | Virginia Tech. https://pubs.ext.vt.edu/APSC/APSC-152/APSC-152.html
4. Clauer, P. J., and Jacobs, L. 2018. Leg and Foot Disorders in Domestic Fowl. Virginia Cooperative Extension publication | Virginia Tech. http://pubs.ext.vt.edu/2902/2902-1098/2902-1098.html
5. Clauer, P. J., and Jacobs, L. 2018. Transporting poultry in a humane manner. Virginia Cooperative Extension publication | Virginia Tech. https://pubs.ext.vt.edu/2902/2902-1088/2902-1088.html
6. Clauer, P.J., Jacobs L., 2018. Raising Fowl and Small Animals in Urban Areas. Virginia Cooperative Extension publication | Virginia Tech. https://www.pubs.ext.vt.edu/2902/2902-1086/2902-1086.html