Animal welfare is fundamental to veterinary ethics, decision making and practice. More importantly, it is fundamental to animals. Formally, biological and legal principles for animal welfare date back at least 400 years and much has been done to constantly expand and embolden the key principles and provisions that help us safeguard them. Thankfully, during the past few decades, animal welfare has broadly ceased to be considered as either a side issue or a scientifically “soft” subject. Instead, it now firmly occupies its place within the formal domain of science and is well represented by numerous dedicated journals, countless peer-reviewed publications and the law. Nevertheless, our knowledge of animal welfare principles constantly needs refreshing.
The principles of animal welfare
Reassuringly, in a sense, there are too many animal welfare principles to cover herein, but at least one can appreciate their diversity in this quick look. Table 1 sets out some key and increasingly promoted principles in animal welfare science.
The heart of animal welfare science is shifting to the new central paradigm of how animals may feel
Essentially, these moderately technical principles also have vital philosophical evaluations built in. For example, an animal could be physically healthy, feeding, growing and remaining free of disease, yet may be deprived of the ability to act on its motivations and choose an alternative place or habitat. Essentially the animal in this situation may be a mentally miserable individual experiencing poor welfare. Conversely, an animal could harbour terminal cancer, but if the animal feels well, even an unhealthy and/or dying individual may be experiencing good welfare. Perhaps unsurprisingly, the heart of animal welfare science is shifting to the new central paradigm of how animals may feel. Somewhat peripheral but clearly vital is the rapidly expanding plethora of established and emerging welfare indicators and related algorithms to help gauge what feelings kept animals (from domestic to exotic) may be experiencing.
| Principle | Summary description | Example resources |
| The five freedoms | Freedom from hunger and thirst Freedom from discomfort Freedom from pain, injury Freedom to express normal behaviour Freedom from fear and distress |
FAWC (1979) |
| Motivation and preference | The ability to express preferences – to choose according to motivation. For example, habitat selection or performing exploratory behaviours | Dawkins (1990) |
| Control over environment | Welfare is linked to the animal’s control over its interactions with the environment and, thus, homeostasis and survival. Animals lacking control over their environment frequently develop a raft of negative states, including stereotypies, aggression, sedentarism, learned helplessness, hyperactivity, exploratory and escape activities, stress, immunosuppression and disease | Dawkins (1990); Broom (1991) |
| The three Fs | Freedom – animals should lead natural lives Function – animals should feel and experience normal pleasures Feelings – animals should function well and experience normal physiological and behavioural function |
Fraser et al. (1997) |
| The five welfare needs | Need for a suitable environment Need for a suitable diet Need to be able to exhibit normal behaviour patterns Need to be housed with or apart from other animals Need to be protected from pain, suffering, injury and disease |
RSPCA (2005) |
| Controlled deprivation | Regardless of enrichment, captive animals probably experience inferior conditions when compared to nature. Essentially, even the best conditions equate to a basic “life-support system” rather than meeting holistic biological needs | Burghardt (2013) |
| The five welfare domains | Nutrition (negative versus positive) Environment (negative versus positive) Health (negative versus positive) Behaviour (negative versus positive) Mental (negative versus positive) = “A life worth living” |
Mellor (2016) |
| Positive and negative states | The promotion of positive states (favourable feelings, stimulation, pleasure, comfort, quiescence, good mental, emotional and physical health, good welfare) and avoidance of negative states (thwarting of positive states, stress, pain, suffering, understimulation, unfavourable stimulation and poor welfare) | Mellor (2016) |
| Our control, our responsibility | In nature, animals have control over their own welfare, whereas in captivity, humans are in control of their welfare and thus hold high responsibility | Mendl et al. (2017) |
| Sentience | Sentience recognises and embraces the capacity to feel positive, neutral and negative experiences (such as pleasure, pain, enjoyment and suffering, etc), as well as to experience consciousness and self-awareness | Mendl et al. (2017) |
| If it leaves, does it come back? | If opening a cage door results in the animal leaving and returning, then captive conditions and welfare may be favourable (or is it merely dependent on basic sustenance?). If the animal does not return, then welfare may be unfavourable | Peng and Broom (2021) |
| Crypto-overcrowding | The inability for all animals in an enclosure to simultaneously use any facility or furnishing. For example, all animals must be able to occupy a water vessel or basking site at the same time | Arena and Warwick (2022) |
Final thoughts
Some animal welfare principles, notably the “five freedoms”, constitute stock material that underpins legal frameworks – such as the UK’s Animal Welfare Act – as well as many research projects and general husbandry guidelines. The strength of the “five freedoms” largely resides in the capacity to provide for the basics but not much more. That said, if read to their fullest, these provisions – especially the “freedom to express normal behaviour” – could arguably go a long way to curtail some abuses of spatial limitations levied on most, if not all, captive animals. Principles encapsulated in the “three Fs” and “five welfare needs” advance elements of the “five freedoms” from being somewhat aspiration-based to requirement-based. “Controlled deprivation”, “Our control, our responsibility” and “Crypto-overcrowding” principles are largely cautions, reminding ourselves about getting husbandry wrong, if not getting it right.
The really interesting animal welfare principles have been there almost from the start, are expanding exponentially and are here to stay
But the really interesting animal welfare principles have been there almost from the start, are expanding exponentially and are here to stay. “Motivation and preference”, “The five welfare domains”, “Positive and negative states”, “Sentience” and “If it leaves, does it come back?” are possibly the true tell-alls of welfare because they recognise animal-centric needs rather than person-perceived targets. If properly acted on by humans, these principles essentially allow animals to take back control of their lives, which is at least some way towards how things should be!
