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. 
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)...

Machado, M., Freitas Silveira, R. M., Machado Bittar, C. M. et al. 2023. Can the emotional state of calves be noticed by their facial expression and heart rate? Applied Animal Behaviour Science 260, 105874.

The aim of this study was to identify whether or not dairy calves change their facial expression and heart rate according to their emotional state when subjected to a stroking or umbrella stimulus. Thirty-two mixed-breed...

Lecorps, B., Woodroffe, R. E., von Keyserlingk, M. A. G. et al. 2023. Hunger affects cognitive performance of dairy calves. Biology Letters 19(1), 20220475.

Hunger remains a significant animal welfare concern as restricted feeding practices are common on farms. Studies to date have focused on negative effects on health and productivity but little research has addressed the feeling of...

Szabo, B., Ringler, E. 2023. Fear of the new? Geckos hesitate to attack novel prey, feed near objects and enter a novel space. Animal Cognition 26(2), 537–549.

Neophobia, the fear of novelty, is an ecologically important response which enables animals to avoid potentially harmful situations. Neophobia is a cognitive process by which individuals distinguish novelty from familiarity. In this study, we aimed...

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...

Schnaider, M. A., Heidemann, M. S., Silva, A. H. P. et al. 2022. Vocalization and other behaviors as indicators of emotional valence: The case of cow-calf separation and reunion in beef cattle. Journal of Veterinary Behavior 49, 28-35.

Vocalization may communicate the emotional state in vocal animals. We aimed to describe and compare vocalization and other behavioral signs of cow-calf pairs in emotionally negative and positive situations, and the potential influence of genetic...

Thompson, J. S., Hudson, C. D., Huxley, J. N. et al. 2022. A randomised controlled trial to evaluate the impact of indoor living space on dairy cow production, reproduction and behaviour. Scientific Reports 12(1), 3849.

As a global society, we have a duty to provide suitable care and conditions for farmed livestock to protect animal welfare and ensure the sustainability of our food supply. The suitability and biological impacts of...

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...

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...

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...

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...

Park, R. M., Foster, M., Daigle, C. L. 2020. A scoping review: The impact of housing systems and environmental features on beef cattle welfare. Animals 10(4), 565.

Housing systems and environmental features can influence beef cattle welfare. To date, little information has been synthesized on this topic. The aim of this scoping review was to examine the relationship between housing and welfare...

Lecorps, B., Nogues, E., von Keyserlingk, M. A. G. et al. 2020. Pessimistic dairy calves are more vulnerable to pain-induced anhedonia. PLOS ONE 15(11), e0242100.

Pain induces deficits in appreciation of rewards (i.e. anhedonia) and variation in response to pain may be partly explained by individual differences in general expectations (i.e. optimism). Dairy calves are routinely subjected to painful procedures...

Cortese, M., Brščić, M., Ughelini, N. et al. 2020. Effectiveness of stocking density reduction on mitigating lameness in a Charolais finishing beef cattle farm. Animals 10(7), 1147.

This study aimed at assessing whether a reduction in stocking density (SKD) would mitigate lameness and positively affect the performance and health of Charolais bulls in an Italian commercial farm. Bulls were distributed in groups...

McMahon, S. A., Wigham, E. 2020. ‘All Ears’: A questionnaire of 1516 owner perceptions of the mental abilities of pet rabbits, subsequent resource provision, and the effect on welfare. Animals 10(10), 1730.

Pet rabbit welfare is a hidden crisis: Inappropriately housed, fed, and not routinely provided healthcare—rabbits can often suffer painful conditions and shortened lifespans. This study provides novel understanding of owners’ perceptions of rabbits’ mental capabilities...

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...

Battini, M., Agostini, A., Mattiello, S. 2019. Understanding cows' emotions on farm: Are eye white and ear posture reliable indicators? Animals 9(8), 477.

Understanding the emotions of dairy cows is primarily important in enhancing the level of welfare and provide a better life on farm. This study explored whether eye white and ear posture can reliably contribute to...

Brscic, M., Dam Otten, N., Contiero, B. et al. 2019. Investigation of a standardized qualitative behaviour assessment and exploration of potential influencing factors on the emotional state of dairy calves. Animals 9(10), 757.

Assessing emotional states of dairy calves is an essential part of welfare assessment, but standardized protocols are absent. The present study aims at assessing the emotional states of dairy calves and establishing a reliable standard...