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Does Stress Affect Decision-Making in Laying Hens?

MSc Thesis: Effects of Stress and Balance of Options on Decision-Making in Laying Hens

The first question most non-biologists ask me whenever I tell them about my Master’s Project is: Can hens actually make decisions?

The answer is of course YES! Hens and other animals make decisions on a daily basis. Not the same kind of important decisions we often think about such as which career to choose or which university to study at. Animals make decisions about things like when or where to feed, sleep or find a suitable partner. However, some decisions made by animals can be very important such as to fight or flee.

We use animals’ decisions in animal welfare research to understand their behavioural needs and demands. In preference tests, animals can choose between e.g. different environments, food items or the opportunity to perform a specific behaviour. Results from these types of tests can then be used to make recommendations and regulations about animal handling and husbandry. It is therefore important to understand which factors that can affect decision-making in animals and how they affect it. One of those possible factors that may be of importance to this field of research is stress. Stress has been shown to affect cognitive processes such as learning and memory and could therefore also have an effect on animal decision-making.

Therefore, the aims of this study were to:

  •   To investigate the effects of stress on decision-making in laying hens
  •   To study physiological and behavioural responses during both easy and difficult decisions

This project was carried out at Bristol Veterinary School, the University of Bristol, between September 2011 until March 2012 in cooperation with the Animal Welfare & Behaviour Research Group.



Professor Christine Nicol, the University of Bristol

Professor Per Jensen, Linköping University

Responsible for this page: Agneta Johansson
Last updated: 04/26/12