Introducing the 5 domains model

Animal welfare science has evolved significantly over the past few decades, moving beyond a narrow focus on the absence of suffering toward a more holistic understanding of animals’ lived experiences. One of the most important developments in this field is the Five Domains Model, which provides a structured, evidence-based approach to assessing and improving animal welfare across species.

What Is the Five Domains Model?

The Five Domains Model was originally developed by Mellor and Reid (1994) and has since been refined to reflect advances in animal welfare science (Mellor et al., 2020). The model consists of four physical or functional domains that influence a fifth, central domain:

1. Nutrition – access to sufficient, appropriate food and water
2. Physical Environment – comfort, shelter, temperature, and safety
3. Health – injury, disease, functional impairment, and fitness
4. Behavioural Interactions – opportunities for species-appropriate behaviour and positive social interactions
5. Mental State – the animal’s overall affective experience, including both negative and positive emotional states

The first four domains contribute directly to the fifth domain, Mental State, recognising that welfare is ultimately about how animals feel, not just how they function.

Why the Five Domains Model Is Important

The Five Domains Model is important because it explicitly acknowledges animals as sentient beings capable of experiencing a range of emotional states, from pain, fear, and frustration to comfort, pleasure, and contentment (Mellor, 2016).

Rather than simply identifying and minimising harm, the model encourages caregivers, professionals, and organisations to:

• Identify welfare risks systematically
• Understand how physical conditions translate into emotional experiences
• Actively promote positive welfare states, not just reduce negative ones

This makes the model particularly valuable in settings such as companion animal care, animal shelters, veterinary practice, wildlife management, farming, research, and training environments.

Why the Five Domains Model Is Better Than the Five Freedoms

The Five Freedoms, developed in the 1960s, played a crucial role in shaping early animal welfare standards. They focus on freedom from hunger, discomfort, pain, fear, and the freedom to express normal behaviour. While groundbreaking for their time, the Five Freedoms have important limitations.

Firstly, the Five Freedoms are largely framed around the absence of negative states, implying that good welfare is achieved once suffering is removed. Modern welfare science recognises that this is insufficient — animals can be free from suffering yet still experience poor welfare due to boredom, frustration, or lack of positive engagement (Mellor & Beausoleil, 2015).

Secondly, the Five Freedoms are often interpreted as absolute states, which are unrealistic in real-world contexts. Complete freedom from discomfort or fear is neither achievable nor biologically appropriate in many situations.

In contrast, the Five Domains Model:

• Recognises welfare as a spectrum, not a binary state
• Integrates physical conditions with mental and emotional outcomes
• Encourages the provision of positive experiences, such as play, exploration, social bonding, and choice
• Is adaptable across species and contexts, from domestic animals to wildlife

This makes the Five Domains Model a more practical, scientifically robust, and ethically progressive framework for assessing and improving animal welfare.

The Role of the Five Domains in Modern Animal Care

Today, the Five Domains Model is widely used by veterinarians, welfare organisations, researchers, and regulatory bodies to guide welfare assessments and decision-making (Mellor et al., 2020). It aligns closely with contemporary understandings of animal cognition, emotion, and behaviour, and supports a proactive approach to welfare improvement.

By shifting the focus from simply preventing harm to actively creating lives worth living, the Five Domains Model represents a major step forward in how we understand and advocate for animal welfare.

The Five Domains Model reflects the growing recognition that animal welfare is not just about survival or the absence of suffering, but about quality of life. By integrating physical health, environment, nutrition, and behaviour with mental and emotional experiences, it provides a comprehensive and compassionate framework for welfare assessment.

As animal professionals, educators, and caregivers, adopting the Five Domains Model allows us to make better-informed decisions and to truly place animal wellbeing at the centre of our work.

References

Mellor, D. J., & Reid, C. S. W. (1994). Concepts of animal well-being and predicting the impact of procedures on experimental animals. In Improving the Well-being of Animals in the Research Environment.

Mellor, D. J. (2016). Updating animal welfare thinking: Moving beyond the “Five Freedoms” towards “A Life Worth Living”. Animals, 6(3), 21.

Mellor, D. J., Beausoleil, N. J., Littlewood, K. E., McLean, A. N., McGreevy, P. D., Jones, B., & Wilkins, C. (2020). The 2020 Five Domains Model: Including human–animal interactions in assessments of animal welfare. Animals, 10(10), 1870.