Refined Handling FAQs

Once staff and mice are adequately trained, husbandry tasks and experimental procedures typically do not take any longer than with tail handling. In fact, one study found cage change times were 10-25 minutes faster per 100 cages when comparing tunnels to forceps after 1-2 change cycles (Reynolds, 2022). For cup handling, typically some habituation for the mice is required so it may take longer initially. 

A study performed at Charles River found that it took between 4-6 weeks for times to stabilize once switching to refined handling. Importantly, even during this initial time while staff were adjusting to the new methods there was no significant increase in error rates (e.g., misgendering, miscounting pups, or missed clinical observations).  

P403: CRiver DAM: Collection Preview 

The benefits of refined handling persist even after standard or aversive procedures as long as the mouse is removed from the home enclosure via refined handling. These procedures include: 

• Scruff or tail restraint (Hurst & West 2010; Roughan & Sevenoaks 2018; Gouveia & Hurst 2019; Henderson et al., 2020) 
• Subcutaneous or intraperitoneal injection (Gouveia & Hurst, 2019; Henderson et al. 2020) 
• Anesthesia (Henderson et al. 2020)  
• Oral gavage (Nakamura & Suzuki, 2018) 

Research shows that it’s not restraint or aversive procedures alone that are stressful. Rather, the combination of the restraint or aversive procedures + tail handling is stressful. 

Home cage tunnels/huts are not necessary to gain benefits from refined handling. However, keeping tunnels/huts in cages is beneficial as they provide enrichment, decrease training time as the mice are already familiar with the tunnel/hut, and support biosecurity. If tunnels/huts are not possible, cup handling is always a good alternative and is even preferred by some strains of mice. 

Note: to prevent cage leaks from home cage tunnels/huts, be sure to place the tunnel/hut away from the water valve and  parallel along the side of the cage. 

Tunnels/huts can be acquired from vendors such as Datesand, Braintree, LBS  Biotechnology, SerLab, Bio-Serv, etc. or from independent providers (e.g., https://www.petroextrusion.com/). Prices vary depending on the vendor and quantity, but can range from $4.00 – $10.00 (USD) each.

Tunnels/huts should be appropriate for the size of the cage. Huts are a suitable alternative to tunnels for refined handling (Bodnar, 2025). 

Not sure where to start? At some institutions, 3.5 inch square tunnels work well as they won’t become improperly wedged in the cages, and can provide an area for a breeding dam to pull up her pups in case of cage flooding.

If you already use cardboard tunnels/huts those are a great alternative. However, if purchasing new tunnels/huts, clear plastic is recommended. This is to allow for mouse visualization during health inspections and to easily slide the mouse out after they are picked up.

Tunnel/hut handling has successfully been used in BSL2 and BSL3 laboratories and with immune-compromised mice (Doerning et al. 2019). Tunnels/huts can be ordered in autoclavable material or purchased pre-irradiated to support biosecurity measures. See the Biosecurity section of the ‘Operations and Tunnels/Huts’ tab for more information.

When working in isolators many handlers find that cup handling is a preferred refined handling style over tunnel/hut handling. This is due to cage size and maneuverability while wearing isolator gloves. 

Thus far, refined handling has been beneficial for all strains tested and both sexes (though males of some strains may take a bit longer to train). Strains tested thus far include BALB/c, CD1s, C57BL/6, DBA/2, and ICGN. These methods were also developed for handling wild-caught mice (Hurst & West 2010).

Some strains prefer cup handling, especially more sensitive strains. More aggressive or jumpier strains do better with tunnel handling.  

Refined handling methods have been shown to increase the reliability of behavioral data, by increasing exploratory behavior and test performance (Gouveia & Hurst 2017). The stress of tail handling may be a research confound and is thought to contribute to the failure to replicate behavioral experimental results, as animals are more anxious and cautious (Gouveia & Hurst 2017). Thus, refined handling may actually improve the accuracy and reliability of research data.  

Generally, no. Best practice in experimental design recommends keeping all variables consistent throughout a study period. Therefore, we do not recommend switching handling techniques mid-study. It is possible it could confound your data. 

It is possible that your current or past research is measuring the stress response to tail handling, and not the variables or test articles that you are researching. You will be practicing better quality science once you remove extraneous variables from your research. It may be appropriate to run a small pilot study or include a control cohort to document the degree to which handling methods impact your research or reach out to others conducting similar research to ask about their handling style.