Why Measure Emotion in Poultry? Because It Matters!

As animal welfare science has evolved, the importance of using animal-based measures to study welfare has become apparent. Poultry may have needs and feelings that are not immediately obvious to humans, and their priorities are influenced by an evolutionary history that is vastly different than our own. Assessing these emotions can indicate what truly matters to the animal and provide the opportunity to improve their quality of life. Researchers can decode clues given by the birds to understand their feelings, likes, and dislikes, and provide them with an environment they most prefer.

Animal Welfare 101

The earliest conceptions of animal welfare began in the 1960s with the formulation of the Five Freedoms (Webster 2016). The Freedoms were the first steps in recognizing the importance of quality of life for animals.

However, as researchers have continued to learn more about animal welfare, the importance of subjective states has emerged as a way to refine how to ensure that animals actually gain the benefits people provide to them (Mellor 2017).

The Five Freedoms

1. Freedom from hunger and thirst.

2. Freedom from discomfort.

3. Freedom from pain, injury, and disease.

4. Freedom to express normal behavior.

5. Freedom from fear and distress.

The Five Freedoms focus on preventing negative states that were easily observable by looking at an animal’s environment, such as food, water, and medical care.

More recent developments in animal welfare science recognize that quality of life is, at its core, subjective and individual. In other words, quality of life is based on how the animal experiences their life from their own perspective. This is reflected in the Five Domains model (fig. 1; Mellor 2017).

Emotion and Quality of Life

The brains of many mammals and birds have specialized systems that help them interpret their experiences, giving rise to emotions (Kret et al. 2022). Basic emotions — including fear, distress, happiness, and enjoyment — are present in many species because they inform animals about the safety and suitability of their behavior and environment (Marino 2017; Panksepp 2005).

In natural environments, this ability is vital to ensure animals continue to do things that benefit their survival or reproduction and avoid things that are harmful to survival or reproduction. When it comes to how an animal experiences their life, emotion is the lens through which they view the world (Marino 2017). Therefore, when trying to measure quality of life, emotion is an important focus.

Measuring Emotions

Emotions exist as a combination of neurological, psychological, and physiological responses (Manstead et al. 2004). An animal senses these biological changes (i.e., has a “feeling”), which result in changes in how it interprets its environment and how it behaves.

Emotions can be detected via investigation of any of these responses (Anderson and Adolphs 2014). For example, during anxiety, an animal may show a physiological fight- or-flight response, more attention directed at a threat, or behaviors associated with vigilance, like freezing in place. Emotions can impact these responses, and similarly, these behavioral, neurological, or physiological responses can impact emotions (fig. 2).

How Does Measuring Emotion Improve Poultry Welfare?

Poultry can show negative emotional states in environments that are overcrowded or lack enrichment and resources (Vas et al. 2023). This is important because while these environments look “unnatural,” which might seem bad for welfare, it cannot be assumed that birds actually experience them this way. It was necessary to test the birds’ responses to the environment to get their perspective on it, rather than relying on a human idea of what is or is not natural.

Furthermore, there is increasing recognition of the importance of providing opportunities for positive emotional states so that animals can experience a life truly worth living (fig. 3). Behavioral tests can help researchers understand what poultry like and want in their environments.

Measures of emotion help animal welfare scientists prevent human bias from impacting their recommendations. They can provide information about what matters to these birds – what motivational drives they need to be met to live a good life, and which interventions provide benefits they actually value.

Conclusion

Many animal species, including poultry, experience emotions. Emotions indicate environmental suitability and safety; they also motivate avoidance of harm and approach to beneficial situations. Assessing these emotions can indicate what actually matters to animals, providing the opportunity to improve their quality of life. By measuring behavior and physiological changes, researchers can get a “bird’s eye view” of how welfare interventions actually improve the lives of poultry.

Additional Resource

This publication was modified from the authors’ 2025 article, “Why Measuring Emotions in Poultry Matters,” published in Poultry Press, no. 66, Poultry Extension Collaborative Newsletter, https://drive.google.com/file/ d/1iRnjQx_b3SiesDmjbyKdHc9nYmufigdY/view.

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