Evaluating environmental enrichment FAQs

It is uncommon for commercially available enrichment items to have been validated in animal studies before sale. Even if enrichment items have been validated during the development process, the animals used may have had different characteristics to those under your care. Strain, sex, age, reproductive status and group composition can all influence how animals may respond to enrichment. It is a good idea to evaluate enrichment for your animals specifically.

Visual checks, made alongside your daily observations, are a good place to start, but you might want to consider taking these further for a more thorough evaluation. You will generally be able to see whether an enrichment item is being used by looking for visual evidence, such as the item being gnawed or otherwise manipulated. However, further observations will be required to understand more about how the enrichment is being used, by which animals and when (this is especially important for nocturnal species). Visual checks will not show you whether animals prefer one type of enrichment to another over time, or pick up on more subtle effects, such as an increase in positive or negative social interactions. Observations should be recorded so you are not relying on memory to determine if any changes have occurred. To have confidence in your evaluation a systematic and scientific approach is recommended. Following a step-by-step procedure, where only one thing differs between the groups you want to compare (e.g. before and after enrichment) will help you to rule out other factors that may cause changes in behaviour or welfare state.

If you work with different strains of laboratory animals, you may have noticed that they can behave differently to each other. Sometimes these differences are so great that you can tell one strain from another by behaviour alone. Because of these differences, it is recommended to evaluate new enrichment items and practices (e.g. rotating different enrichment items for novelty) on a strain-by-strain basis.  Within strains, age and pregnancy status are other factors that should be taken into account when considering enrichment suitability; the needs of animals can change at different life stages. Some scientific procedures may also alter animals’ enrichment requirements, or restrict the kinds of items that can be provided.

While you may be enthusiastic about getting involved in an enrichment project, it can be difficult to fit new tasks into an already busy schedule. There are certain approaches you can take to decrease the amount of extra time required for the study itself. These include sharing the workload through collaboration with others, and incorporating data into your study that can be easily collected during everyday husbandry (e.g. weighing chews blocks, or scoring nest quality). Ideally, you will be able to have some project time dedicated to your enrichment study. This will require a discussion with your manager. You can also ask for support from your AWERB, IACUC or equivalent.

This will depend on what you have available at your facility, and what type of enrichment you are planning to introduce. You may need to borrow equipment, such as a video camera, or you may be able to conduct an evaluation with little more than a pen and paper. If you are planning on evaluating a specific enrichment item that would need to be purchased, it could be possible to obtain some free samples by approaching the suppliers. This would allow you to conduct a small-scale evaluation of the suitability of the enrichment, allowing you to assess whether any welfare benefits are observable, before making a larger (and more expensive) order. Costs can be cut by getting creative with whatever is available within your facility. This can include changing the way enrichment is presented to the animals; for example, treats could be hidden within existing structures, current enrichment could be rotated weekly, or different combinations of nesting material could be provided. Remember that enrichment does not always mean physical objects. The sensory and social experiences of the animals also contribute to their welfare and these are more likely to involve making changes to husbandry rather than making large purchases.

To address this, good communication and coordination with your colleagues, including researchers, will be necessary. It may be the case that only a few animals are available at one time, which may mean a small-scale study, or staggering your data collection over a longer period as more animals become available. While studies using fewer animals have limitations, any systematic evaluation of enrichment can be valuable for providing insight into enrichment suitability and for identifying potential benefits or concerns. Just remember to ensure that you are evaluating enrichment using the same type of animal (e.g. strain and age) that you plan to use the enrichment for and that you take steps to ensure that the data you collect is high quality.

Although it is widely acknowledged that ‘better welfare means better science’, in practice you may encounter beliefs that new, or different, enrichment may conflict with experimental endpoints or historical data. Open minds are essential, and involving researchers in the design of your study may help to address any concerns.  We would encourage anyone concerned about enrichment and standardisation to read this paper by Hanno Würbel and Joe Garner. The topic of enrichment and standardisation is also covered in this review paper by Vera Baumans. There are questions around how useful standardisation is for generating reproducible and translatable results in animal studies. Although it does not relate directly to enrichment, this video goes into more detail on this topic.

This resource has been created for use by animal technicians, so previous experience of research is not assumed. As a starting point, we suggest working through this web resource and reading what to consider before you begin. There are also example protocols to help you plan a study of your own and advice on how to improve the scientific quality of your evaluation. We hope that these resources help you on your way, but if you feel like you need some extra help, ask a colleague who has a research background. Some facilities have support in place specifically for 3Rs-focused initiatives; your manager may be able to advise you on this.

The number of animals that technicians have access to can vary widely, as can the amount of time available to invest into a study. If it is not feasible to meet the requirements of statistical analyses, such as sufficient sample sizes, it is still possible to use scientific principles (such as following a methodical plan) to conduct a basic evaluation of enrichment. 

Due to the large variation in available animals, study type and access to resources, it would be inappropriate to provide ‘catch-all’ guidance on animal numbers and statistical analyses. It is also likely that the caveats required for this type of guidance would distract from the aim of this web resource, which is to help animal technicians to conduct any systematic evaluation of environmental enrichment and improve the quality of the data they collect.

To avoid creating barriers to evaluating enrichment, the guidance for interpreting data in this resource focuses on simple and accessible ways to summarise and visualise data, rather than carrying out formal statistical tests. If your aim is to carry out formal statistical tests on your data, you should consult a statistician, or someone with statistical expertise, for guidance on how to design your study. Your AWERB, IACUC or equivalent should be able to help you find one.

Communicate, collaborate and share the work with colleagues! Even with the help of this resource no one expects you to be able to carry out all aspects of an evaluation alone. By working with your colleagues you can share the tasks based on your strengths, weakness and the aspects that each of you find more enjoyable.