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. 
Crump, A., Gibbons, M., Barrett, M. et al. 2023. Is it time for insect researchers to consider their subjects’ welfare? PLOS Biology 21(6), e3002138.

Recent evidence suggests that at least some insect species might plausibly feel pain. These findings should prompt researchers to think about the welfare implications of insect experiments.

Evans, L., Brooks, G. C., Anderson, M. G. et al. 2023. Environmental complexity and reduced stocking density promote positive behavioral outcomes in broiler chickens. Animals 13(13), 2074.

The objective was to evaluate the impacts of a complex environment and stocking density on Ross 708 broiler chicken behaviors. Eight pens contained either high complexity (HC) or low complexity (LC) environments, and high (HD)...

Parsons, M., Stryjek, R., Fendt, M. et al. 2023. Making a case for the free exploratory paradigm: Animal welfare-friendly assays that enhance heterozygosity and ecological validity. Frontiers in Behavioral Neuroscience 17, 1228478.

Animal welfare considerations are an essential part of scientific research. If animals may suffer, then even 26 the most promising research plans can be delayed or rejected and the resulting data may be questionable. 27...

Sen Sarma, O., Frymus, N., Axling, F. et al. 2023. Optimizing zebrafish rearing−Effects of fish density and environmental enrichment. Frontiers in Behavioral Neuroscience 17, 1204021.

Despite its popularity in research, there is very little scientifically validated knowledge about the best practices on zebrafish (Danio rerio) husbandry, which has led to several facilities having their own husbandry protocols. This study was...

Buenhombre, J., Daza-Cardona, E. A., Sousa, P. et al. 2023. Structural environmental enrichment and the way it is offered influence cognitive judgement bias and anxiety-like behaviours in zebrafish. Animal Cognition 26, 563–577.

Environmental enrichment in zebrafish generally reduces anxiety-related behaviours, improves learning in maze trials and increases health and biological fitness. However, certain types of enrichment or certain conditions induce the opposite effects. Therefore, it is essential...

Lupfer, G., Brandenburger, A., Machado, M. et al. 2023. Ultrasonic vocalizations near 30 kHz may indicate excitement rather than distress in female Wistar rats. Applied Animal Behaviour Science 261, 105881.

Rats emit ultrasonic vocalizations (USVs), sometimes referred to as 50-kHz vocalizations, during activities such as play and lower-frequency USVs, sometimes referred to as 22-kHz vocalizations, when experiencing distress. Definitions of 22-kHz vocalizations vary in terms...

Fontana, B. D., Alnassar, N., Parker, M. O. 2023. Transgenerational effects of early-life stress on anxiety behavior in zebrafish (Danio rerio). Behavioural Processes 208, 104874.

Early-life adversity impacts on anxiety-related behaviors in adulthood. The effects of such adversity not only affect the animal itself, but can be passed on transgenerationally. Pervasive effects of experimentally-induced early-life stress (ELS) have been documented...

Clark, F. E. 2023. In the zone: Towards a comparative study of flow state in primates. Animal Behavior and Cognition 10(1), 62–88.

Flow is an altered state of feeling ‘in the zone’ when fully absorbed in a challenge and is associated with positive affective state (feelings). Despite almost five decades of research, Flow has not yet been...

Elwood, R. W. 2023. Behavioural indicators of pain and suffering in arthropods and might pain bite back? Animals 13(16), 2602.

Pain in response to tissue damage functions to change behaviour so that further damage is minimised whereas healing and survival are promoted. This paper focuses on the behavioural criteria that match the function to ask...

Stevens, C., Hammonds, T., Hinchcliffe, J. et al. 2023. Report of the 2022 RSPCA/UFAW Rodent Welfare Group Meeting. Animal Technology and Welfare 22(2), 91–100.

The RSPCA/UFAW Rodent Welfare Group has held a one-day meeting every autumn for the last 29 years, so that its members can discuss current welfare research, exchange views on welfare issues and share experiences of...

Xue, B., Ma, Y.-Y., Zhu, J.-Y. et al. 2023. Chronic social comparison elicits depression- and anxiety-like behaviors and alterations in brain-derived neurotrophic factor expression in male rats. Animal Cognition 26(5), 1505–1519.

Social comparison is a fundamental human characteristic; however, long-term social comparison may induce psychological stress and can lead to depression and anxiety. Recent studies have shown that nonhuman primates compare themselves with others; however, no...

Mocz, F., Michel, V., Janvrot, M. et al. 2022. Positive effects of elevated platforms and straw bales on the welfare of fast-growing broiler chickens reared at two different stocking densities. Animals 12(5), 542.

In conventional rearing systems, fast-growing broiler chickens commonly experience welfare issues, such as contact dermatitis, walking difficulties or a lack of expression of species-specific behaviours. Enriching their environment may be a way to improve their...

Knaebe, B., Weiss, C. C., Zimmermann, J. et al. 2022. The promise of behavioral tracking systems for advancing primate animal welfare. Animals 12(13), 1648.

Recent years have witnessed major advances in the ability of computerized systems to track the positions of animals as they move through large and unconstrained environments. These systems have so far been a great boon...

Fares, R., Flénet, T., Vial, J. et al. 2022. Non invasive jacketed telemetry in socially-housed rats for a combined assessment of respiratory system, electrocardiogram and activity using the DECRO system. Journal of Pharmacological and Toxicological Methods 117, 107195.

Respiratory and cardiovascular systems are among the vital organ systems that should be studied in safety pharmacology core battery test. Non-invasive jacketed external telemetry technology that enables concomitant monitoring of both systems has been available...

Houstin, A., Zitterbart, D. P., Winterl, A. et al. 2022. Biologging of emperor penguins—Attachment techniques and associated deployment performance. PLOS ONE 17(8), e0265849.

An increasing number of marine animals are equipped with biologgers, to study their physiology, behaviour and ecology, often for conservation purposes. To minimise the impacts of biologgers on the animals’ welfare, the Refinement principle from...

Mason, G. J., Lavery, J. M. 2022. What is it like to be a bass? Red herrings, fish pain and the study of animal sentience. Frontiers in Veterinary Science 9, 788289.

Debates around fishes’ ability to feel pain concern sentience: do reactions to tissue damage indicate evaluative consciousness (conscious affect), or mere nociception? Thanks to Braithwaite’s research leadership, and concerns that current practices could compromise welfare...

Mieske, P., Hobbiesiefken, U., Fischer-Tenhagen, C. et al. 2022. Bored at home?—A systematic review on the effect of environmental enrichment on the welfare of laboratory rats and mice. Frontiers in Veterinary Science 9, 899219.

Boredom is an emotional state that occurs when an individual has nothing to do, is not interested in the surrounding, and feels dreary and in a monotony. While this condition is usually defined for humans...

Saraiva, J. L., Rachinas-Lopes, P., Arechavala-Lopez, P. 2022. Finding the “golden stocking density”: A balance between fish welfare and farmers’ perspectives. Frontiers in Veterinary Science 9, 930221.

The effects of stocking density on fish welfare are complex and involve many interacting parameters. This complex relationship between fish welfare, stocking density and influencing factors make it challenging to define a specific optimal (“golden”)...

Schwarzer, A., Erhard, M., Schmidt, P. et al. 2022. Effects of stocking rate and environmental enrichment on the ontogeny of pecking behavior of laying hen pullets confined in aviary compartments during the first 4 weeks of life. Animals 12(19), 2639.

The objective of this study was to describe the ontogeny of the severe feather pecking (SFP), gentle feather pecking (GFP), aggressive pecking (AP), and enrichment pecking (EP) of non-beak-trimmed Lohmann Brown (LB)-pullets during the first...

van der Eijk, J. A. J., Gunnink, H., Melis, M. et al. 2022. Reducing stocking density benefits behaviour of fast- and slower-growing broilers. Applied Animal Behaviour Science 257, 105754.

The broiler industry has come under sustained pressure from welfare organizations to improve broiler welfare. Breed and stocking density are important factors for broiler welfare and are often specified as criteria for higher welfare systems...

Gilmour, K. M., Bard, B. 2022. Social buffering of the stress response: Insights from fishes. Biology Letters 18(10), 20220332.

Social buffering of stress refers to the effect of a social partner in reducing the cortisol or corticosterone response to a stressor. It has been well studied in mammals, particularly those that form pair bonds...

Sørensen, D., Cloutier, S., Gaskill, B. (Eds.). 2021. Animal-centric Care and Management - Enhancing Refinement in Biomedical Research. CRC Press, Boca Raton, FL.

The concept of the 3Rs (Refinement, Reduction and Replacement) has been used as a framework for improving the welfare of laboratory animals for the last half century. By establishing an animal-centric view on housing and...

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...

Krueger, L. D., Chang, S. E., Motoc, M. et al. 2021. Effects of pair housing on patency of jugular catheters in rats (Rattus norvegicus). JAALAS 60(3), 357-364.

Chronic vascular access devices are widely used in a variety of species for repeated blood sampling or substance administration. Jugular catheters are commonly used for studying addiction-related behaviors in rats. Rats with catheters have historically...

Martini, A., Huysseune, A., Witten, P. E. et al. 2021. Plasticity of the skeleton and skeletal deformities in zebrafish (Danio rerio) linked to rearing density. Journal of Fish Biology 98(4), 971-986.

The teleost zebrafish (Danio rerio), an established model for human skeletal diseases, is reared under controlled conditions with defined parameters for temperature and photoperiod. Studies aimed at defining the proper rearing density have been performed...