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. 
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...

Hall, K., Bryant, J., Staley, M. et al. 2021. Behavioural diversity as a potential welfare indicator for professionally managed chimpanzees (Pan troglodytes): Exploring variations in calculating diversity using species-specific behaviours. Animal Welfare 30(4), 381-392.

Behavioural diversity may serve as a positive indicator of animal welfare that can be applied in long-term monitoring schemes in managed settings (eg zoos, laboratories, farms). Behavioural diversity is often higher when animals live in...

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...

Jacobs, L., Melick, S., Freeman, N. et al. 2021. Broiler chicken behavior and activity are affected by novel flooring treatments. Animals 11(10), 2841.

The objective was to determine broiler chicken behavioral differences in response to novel flooring treatments. Broilers (n = 182) were housed in 14 pens (a random subset from a larger-scale study including 42 pens), with...

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...

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...

Kalafut, K. L., Kinley, R. 2020. Using radio frequency identification for behavioral monitoring in little blue penguins. Journal of Applied Animal Welfare Science 23(1), 62-73.

A common goal of captive animal institutions is to create environments that allow for the most naturalistic behavior from their animals. Behavioral data is often used as a measure of how an animal is thriving...

Goldsborough, Z., van Leeuwen, E. J. C., Kolff, K. W. T. et al. 2020. Do chimpanzees (Pan troglodytes) console a bereaved mother? Primates volume 61(1), 93–102.

Comparative thanatology encompasses the study of death-related responses in non-human animals and aspires to elucidate the evolutionary origins of human behavior in the context of death. Many reports have revealed that humans are not the...

Reese, L., Ladwig-Wiegard, M., von Fersen, L. et al. 2020. Deflighting zoo birds and its welfare considerations. Animal Welfare 29(1), 69-80.

For over a century, the practice of deflighting has taken place in zoological collections in order to ensure birds remain in open-topped enclosures. Over time, efforts have been made to improve or develop new (surgical)...

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...

Ross, S. R., Leinwand, J. G. 2020. A review of research in primate sanctuaries. Biology Letters 16(4), 1620200033.

While non-human primate studies have long been conducted in laboratories, and more recently at zoological parks, sanctuaries are increasingly considered a viable setting for research. Accredited sanctuaries in non-range countries house thousands of primates formerly...

Inoue, N., Shimada, M. 2020. Comparisons of activity budgets, interactions, and social structures in captive and wild chimpanzees (Pan troglodytes). Animals 10(6), 1063.

Chimpanzees in zoos with sufficient and appropriate environmental enrichment devices are expected to exhibit behaviors, interactions, and societies similar to those in the wild. In this study, we compared the activity budgets of each observed...

Watson, H. A study into viable wooden enrichment objects for Syrian hamsters. Animal Technology and Welfare 19(1), 86-88.

Failing to provide hamsters with a method to wear down their teeth can lead to detrimental behaviour such as bar chewing, and health issues, for example, overgrown teeth and tooth loss. However, hamsters use their...

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...

Reinhardt, V. (ed.) 2020. It’s Okay to Cry - Discussions by the Laboratory Animal Refinement & Enrichment Forum [LAREF], Volume V. Animal Welfare Institute, Washington, DC.

This is the 5th volume of selected discussions that took place on the electronic Laboratory Animal Refinement & Enrichment Forum between February 2016 and December 2019. The forum was created in October 2002; it allows...

Allanic, M., Hayashi, M., Matsuzawa, T., 2020. Investigating the function of mutual grooming in captive bonobos (Pan paniscus) and Chimpanzees (Pan troglodytes). Folia Primatologica 91, 481-494.

Social grooming is often exchanged between individuals in many primate species. Rates of bidirectional (or simultaneous mutual) grooming vary across primate species, and its function is not yet fully understood. For example, mutual grooming is...

Bill, J., Rauterberg, S. L., Herbrandt, S. et al. 2020. Agonistic behavior and social hierarchy in female domestic rabbits kept in semi-groups. Journal of Veterinary Behavior 38, 21-31.

In semi-natural mixed-sex groups, rabbits (Oryctolagus cuniculus) organize their social life by forming a hierarchy, which is characterized by linearity and stability. Compared to the natural environment, many factors are different in contemporary breeding systems...

Liu, Z., Torrey, S., Newberry, R. C. et al. 2020. Play behaviour reduced by environmental enrichment in fast-growing broiler chickens. Applied Animal Behaviour Science 232, 105098.

The objective of this study was to evaluate effects of environmental enrichment on play behaviour in fast-growing broiler chickens. Chicks (19 of each sex) were randomly assigned to 6 non-enriched (NE) pens and 6 pens...

Moroki, Y. 2020. Impact of flooring type on the sham dustbathing behaviour of caged laying hens. Applied Animal Behaviour Science 230, 105066.

Feed particles are preferred for foraging and they are also a stimulus for sham dustbathing. Most sham dustbathing bouts start with bill raking in the feed by caged hens. As hens often exhibit a floor...

Yamanashi, Y., Bando, H., Matsunaga, M. et al. 2020. Development of bed-building behaviors in captive chimpanzees (Pan troglodytes): Implication for critical period hypothesis and captive management. Primates 61(5), 639-646.

Wild great apes build beds for sleeping by combining tree branches or other vegetation, but the development of this behavior is poorly understood. We investigated the development of bed-building behaviors by conducting complementary cross-sectional and...

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...