Refinement Database

Database on Refinement of Housing, Husbandry, Care, and Use of Animals in Research

This database, created in 2000, is updated every four months with newly published scientific articles, books, and other publications related to improving or safeguarding the welfare of animals used in research.

Tips for using the database:

  • This landing page displays all of the publications in the database.
  • Use the drop-down menus to filter these publications by Animal Type, Setting, and/or Topic.
  • Clicking on a parent category (e.g., Rodent) will include publications relating to all the items in that category (e.g., Chinchilla, Gerbil, Guinea Pig, etc.).
  • You may also add a keyword to further narrow your search.
  • Please note that at this time, only publications dated 2010 or later (with some exceptions) can be filtered by Animal Type and Topic, and only publications dated 2020 or later (with some exceptions) can be filtered by Setting. Most publications older than 2010 can only be searched by keyword. 
Elwood, R. W. 2022. Hermit crabs, shells, and sentience. Animal Cognition 25(5), 1241–1257.

Hermit crabs have an intimate relationship with gastropod shells and show numerous activities by which they locate, select, and change shells in different contexts. They gather information about new shells and update information about their...

Takahashi, K. 2022. Changes in the anxiety-like and fearful behavior of shrimp following daily threatening experiences. Animal Cognition 25(2), 319–327.

Behavioral variation in animals is often influenced by experience. Previous studies have found that daily threatening experiences can enhance fear- and anxiety-like behaviors in some vertebrates. However, it is unclear whether the change in fear/anxiety...

Phillips, H. N., Heins, B. J. 2021. Effects of outdoor stocking density on growth, feather damage and behavior of slow-growing free-range broilers. Animals 11(3), 688.

Access to pasture is a main benefit of free-range broiler housing systems, yet the level of outdoor stocking density on broiler animal welfare remains unsettled. The growth, feather damage, pasture ranging and behaviors were assessed...

Gehlen, H., Krumbach, K., Thöne-Reineke, C. 2021. Keeping stallions in groups—Species-appropriate or relevant to animal welfare? Animals 11(5), 1317.

This literature review was aimed at analyzing whether stallion husbandry in groups is possible and desirable or poses risks. This was determined on the basis of different studies in order to be able to give...

Krueger, K., Esch, L., Farmer, K. et al. 2021. Basic needs in horses?—A literature review. Animals 11(6), 1798.

Every animal species has particular environmental requirements that are essential for its welfare, and when these so-called “basic needs” are not fulfilled, the animals suffer. The basic needs of horses have been claimed to be...

Anderson, M. G., Campbell, A. M., Crump, A. et al. 2021. Effect of environmental complexity and stocking density on fear and anxiety in broiler chickens. Animals 11(8), 2383.

Barren housing and high stocking densities may contribute to negative affective states in broiler chickens, reducing their welfare. We investigated the effects of environmental complexity and stocking density on broilers’ attention bias (measure of anxiety)...

Travain, T., Valsecchi, P. 2021. Infrared thermography in the study of animals’ emotional responses: A critical review. Animals 11(9), 2510.

Whether animals have emotions was historically a long-lasting question but, today, nobody disputes that they do. However, how to assess them and how to guarantee animals their welfare have become important research topics in the...

Forslind, S., Blokhuis, H. J., Riber, A. B. 2021. Disturbance of resting behaviour of broilers under different environmental conditions. Applied Animal Behaviour Science 242, 105425.

Resting behaviours make up a large part of the daily time budget of broilers. However, in intensive broiler production systems disruptions of resting behaviours occur, where resting individuals get disturbed by active individuals. Such interruptions...

MacLellan, A., Fureix, C., Polanco, A. et al. 2021. Can animals develop depression? An overview and assessment of “depression-like” states. Behaviour 158(14/15), 1303–1353.

Describing certain animal behaviours as 'depression-like' or 'depressive' has become common across several fields of research. These typically involve unusually low activity or unresponsiveness and/or reduced interest in pleasure (anhedonia). While the term 'depression-like' carefully...

Campbell, D. L. M., Lee, C. 2021. A perspective on strategic enrichment for brain development: Is this the key to animal happiness? Frontiers in Veterinary Science 8, 720422.

Livestock animals are sentient beings with cognitive and emotional capacities and their brain development, similar to humans and other animal species, is affected by their surrounding environmental conditions. Current intensive production systems, through the restrictions...

Neethirajan, S. 2021. The use of artificial intelligence in assessing affective states in livestock. Frontiers in Veterinary Science 8, 715261.

In order to promote the welfare of farm animals, there is a need to be able to recognize, register and monitor their affective states. Numerous studies show that just like humans, non-human animals are able...

da Silva Medeiros Elidio, H., Coelho, J. W. R., Cavalcanti Pereira da Silva, L. C. et al. 2021. Housing density and aggression in Syrian hamsters. JAALAS 60(5), 506-509.

The Syrian hamster (Mesocricetus auratus) is a solitary and naturally territorial animal, with female hamsters being more aggressive than males. This behavior makes handling difficult because they are usually housed in groups, which can lead...

Anderson, M. G., Campbell, A. M., Crump, A. et al. 2021. Environmental complexity positively impacts affective states of broiler chickens. Scientific Reports 11(1), 16966.

Affective state can bias an animal’s judgement. Animals in positive affective states can interpret ambiguous cues more positively (“optimistically”) than animals in negative affective states. Thus, judgement bias tests can determine an animal’s affective state...

Armstrong, E. A., Rufener, C., Toscano, M. J. et al. 2020. Keel bone fractures induce a depressive-like state in laying hens. Scientific Reports 10(1), 3007.

In commercial flocks of laying hens, keel bone fractures (KBFs) are prevalent and associated with behavioural indicators of pain. However, whether their impact is severe enough to induce a depressive-like state of chronic stress is...

Raspa, F., Tarantola, M., Bergero, D. et al. 2020. Stocking density affects welfare indicators in horses reared for meat production. Animals 10(6), 1103.

Horses kept for meat production are reared in intensive breeding farms. We employed a checklist adapted from the Animal Welfare Indicators (AWIN) assessment protocol. Our evaluation aims to assess whether welfare indicators are influenced by...

Skinner, M., Miller, N. 2020. Aggregation and social interaction in garter snakes (Thamnophis sirtalis sirtalis). Behavioral Ecology and Sociobiology 74, 51.

Previous research has shown that competition, familiarity, diet, and relatedness can all influence aggregation patterns in garter snakes. We controlled for these factors and examined social aggregation patterns in juvenile Eastern garter snakes (Thamnophis sirtalis...

Elwood, R. W. 2020. Do arthropods respond to noxious stimuli purely by reflex? Animal Sentience 29(10).

Mikhalevich & Powell (2020) argue that it is wrong to dismiss the idea of sentience in invertebrates. Here, I expand on the evidence for crustaceans responding to noxious stimuli in ways that are not explained...

Acharya, R., Rault, J.-L. 2020. Risk factors for feather-damaging behavior in companion parrots: A social media study. Journal of Veterinary Behavior 40, 43-49.

Studies on the etiology of behavioral problems often involve interference in the animal's routine or reliance on owners' self-reports like surveys. Gathering data from videos posted on social media, a technique coined ‘video mining’, offers...

Mott, R. O., Hawthorne, S. J., McBride, S. D. 2020. Blink rate as a measure of stress and attention in the domestic horse (Equus caballus). Scientific Reports 10(1), 21409.

Measuring animal stress is fundamentally important for assessing animal emotional state and welfare. Conventional methods of quantifying stress (cortisol levels, heart rate/heart rate variability) require specialist equipment and are not instantly available. Spontaneous blink rate...

Borland, J. M., Kim, E., Swanson, S. P. et al. 2020. Effect of aggressive experience in female Syrian hamsters on glutamate receptor expression in the nucleus accumbens. Frontiers in Behavioral Neuroscience 14, 583395.

Our social relationships determine our health and well-being. In rodent models, there is now strong support for the rewarding properties of aggressive or assertive behaviors to be critical for the expression and development of adaptive...

Raspa, F., Tarantola, M., Bergero, D. et al. 2020. Time-budget of horses reared for meat production: Influence of stocking density on behavioural activities and subsequent welfare. Animals 10(8), 1334.

Horses reared for meat production can be kept in intensive breeding farms where they are housed in group pens at high stocking densities. The present study aimed to evaluate whether the expressed behaviours correlated with...

Pedersen, I. J., Forkman, B. 2019. Improving leg health in broiler chickens: A systematic review of the effect of environmental enrichment. Animal Welfare 28(2), 215-230.

Leg problems are highly prevalent in modern broiler production and provision of environmental enrichment could be a strategy to improve leg health. Different types of environmental enrichment have undergone evaluation. Our objective was to conduct...

Yngvesson, J., Rey Torres, J. C., Lindholm, J. et al. 2019. Health and body conditions of riding school horses housed in groups or kept in conventional tie-stall/box housing. Animals 9(3), 73.

We compared welfare measures of horses among Swedish riding schools (RS) during winter where horses were kept either in group housing (n = 8) or in tie-stalls/boxes (n = 8), Health data for six previous...

Arechavala-Lopez, P., Saraiva, J. L. 2019. Welfare of Cultured and Experimental Fishes. Basel, Switzerland: MDPI, 132 pages.

This open access book is a printed edition of the Special Issue on Welfare of Cultured and Experimental Fishes that was published in the journal Fishes. The PDF is free for download.

Fife-Cook, I., Franks, B. 2019. Positive welfare for fishes: Rationale and areas for future study. Fishes 4(2), 31.

Traditional animal welfare paradigms have focused on maintaining physical health and mitigating negative impacts to wellbeing. Recently, however, the field has increasingly recognized the importance of positive welfare (i.e., mental and physical states that exceed...