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. 
Malchow, J., Schrader, L. 2021. Effects of an elevated platform on welfare aspects in male conventional broilers and dual-purpose chickens. Frontiers in Veterinary Science 8, 660602.

To avoid killing day-old male chicks, one possibility is to keep dual-purpose chicken strains. Here, the hens were kept for egg production, and the roosters were kept for meat production. Both sexes had moderate performances...

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...

Ellis, T., Katsiadaki, I. 2021. Clarification of early end-points for refinement of animal experiments, with specific reference to fish. Laboratory Animals 55(3), 244-253.

Appropriate end-points are integral to the refinement of laboratory animal experiments. Our recent experience has highlighted that ambiguity around end-points is hampering their adoption in experiments that cause severe suffering to fish. In toxicology, the...

Archer, C. 2021. Zebrafish water quality for laboratory animal technicians. Laboratory Animal Science Professional 9(4) (July/August), 11-13.

Zebrafish are an increasingly popular model organism in many aspects of animal research; however, some aspects of their husbandry needs are quite disparate from that which most lab animal technicians are trained. Possibly the most...

Kittelsen, K. E., Gretarsson, P., Jensen, P. et al. 2021. Keel bone fractures are more prevalent in White Leghorn hens than in Red Jungle fowl hens—A pilot study. PLOS ONE 16(7), e0255234.

Fractures and deviations to the keel bone are common in commercial laying hens, with reported variations in occurrence across strains and breeds. The aetiology is not fully understood, however, modern genetics and selection for efficient...

Norman, K. I., Weeks, C. A., Tarlton, J. F. 2021. Rearing experience with ramps improves specific learning and behaviour and welfare on a commercial laying farm. Scientific Reports 11(1), 8860.

To access resources in commercial laying houses hens must move between levels with agility to avoid injury. This study considered whether providing ramps during rear improved the ability of birds to transition between levels. Twelve...

Diarra, S., Lameta, S., Amosa, F. et al. 2021. Alternative bedding materials for poultry: Availability, efficacy, and major constraints. Frontiers in Veterinary Science 8, 669504.

The increasing demand of wood shavings (WS) and sawdust (SD) by other industries and growing concerns of potential chemical contaminants from wood products have amplified research interest in alternative bedding materials for commercial poultry. Several...

Campbell, D. L. M., Whitten, J. M., Slater, E. et al. 2021. Rearing enrichments differentially modified hen personality traits and reduced prediction of range use. Animal Behaviour 179, 97-109.

Domestic fowl have been demonstrated to individually differ in personality, dictating reactions to environmental stimuli. Free-range chickens, Gallus gallus domesticus, show individual range use variation, which may be related to personality differences. Enrichment can also...

Sans, E. C. O., Tuyttens, F. A.M., Taconeli, C. A. et al. 2021. Welfare of broiler chickens reared under two different types of housing. Animal Welfare 30(3), 341-353.

We compared closed- and open-sided industrial houses with respect to the welfare of broiler chickens in southern Brazil. Ten flocks from each design were evaluated and measures divided into the following categories: i) bird health...

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...

Schwarzer, A., Plattner, C., Bergmann, S. et al. 2021. Feather pecking in non-beak-trimmed and beak-trimmed laying hens on commercial farms with aviaries. Animals 11(11), 3085.

Severe feather pecking (SFP) is a major animal welfare problem in layers. It results in pain and injuries in the affected animal. It was the aim of this study to gain insight into the actual...

Hu, J., Xiong, Y., Gates, R. S. et al. 2021. Perches as cooling devices for reducing heat stress in caged laying hens: A review. Animals 11(11), 3026.

Heat stress is one of the most detrimental environmental challenges affecting the biological process and the related production performance of farm animals, especially in poultry. Commercial laying hens have been bred (selected) for high egg...

de Jong, I. C., Blaauw, X. E., van der Eijk, J. E. J. et al. 2021. Providing environmental enrichments affects activity and performance, but not leg health in fast- and slower-growing broiler chickens. Applied Animal Behaviour Science 241, 105375.

Effects of environmental enrichment on activity, behaviour, walking ability, contact dermatitis and performance were investigated in fast- and slower-growing broiler chickens. A total of 840 day-old male broilers, 420 of a fast-growing strain (Ross 308)...

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...

Powell, C., von Keyserlingk, M. A. G., Franks, B. 2021. Tank cleaning temporarily increases stress and decreases affiliative behavior in zebrafish. Applied Animal Behaviour Science 242, 105414.

Small, tropical fish are popular companion animals and constitute a major proportion of the vertebrates used in scientific research, but little is known about how they are affected by routine husbandry practices. Manual tank cleanings...

Sirovnik, J., Euteneuer, P., König von Borstel, U. 2021. An attempt to use sound-imprinting to attract broilers onto elevated platforms for night-time roosting. Applied Animal Behaviour Science 243, 105448.

Welfare of fast growing broilers is often compromised due to leg health issues. A more complex environment such as the provision of elevated platforms facilitates activity and improves leg health in fast growing broilers. Thus...

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...

Burbano Lombana, D. A., Macrì, S., Porfiri, M. 2021. Collective emotional contagion in zebrafish. Frontiers in Behavioral Neuroscience 15, 730372.

Seeking to match our emotional state with one of those around us is known as emotional contagion-a fundamental biological process that underlies social behavior across several species and taxa. While emotional contagion has been traditionally...

DePasquale, C., Kemerer, N., White, N. et al. 2021. The influence of an enriched environment in enhancing recognition memory in zebrafish (Danio rerio). Frontiers in Veterinary Science 8, 749746.

Environmental enrichment is used to increase social and physical stimulation for animals in captivity which can lead to enhanced cognition. Fundamental to the positive effect enrichment has on the brain is that it provides opportunities...

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...

Lourenço da Silva, M. I., Almeida Paz, I., Chaves, G. et al. 2021. Behaviour and animal welfare indicators of broiler chickens housed in an enriched environment. PLOS ONE 16(9), e0256963.

The present study aimed to assess the influence of adding straw bales, step platforms, and laser projectors as environmental enrichment resources on the behaviour and welfare indicators of broiler chickens (Gallus gallus domesticus). A sample...

Sabrautzki, S., Miller, M., Kague, E. et al. 2021. Welfare assessment of adult laboratory zebrafish: A practical guide. Zebrafish 18(4), 282-292.

Teleost fish such as Danio rerio (zebrafish) have been successfully used in biomedical research since decades. Genetically altered fish lines obtained by state-of-the-art genetic technologies are serving as well-known model organisms. In Europe, following Directive...

Andersson, M., Kettunen, P. 2021. Effects of holding density on the welfare of zebrafish: A systematic review. Zebrafish 18(5), 297-306.

The zebrafish is becoming an increasingly popular research animal around the world. Its welfare is affected by an array of environmental factors, such as food access and water quality. Holding density is an important welfare...