Ferrets are used as a primary influenza research model due to their susceptibility to human flu strains, with specific welfare implications.
Ferrets in influenza challenge experiments experience genuine illness including fever, nasal discharge, reduced activity, and respiratory distress for days to weeks. This illness causes real suffering. Post-challenge isolation violates their strong social needs. Welfare monitoring and analgesic support can reduce but not eliminate suffering inherent in challenge experiments. The absence of strong non-animal alternatives for influenza transmission research means this welfare cost continues. Welfare refinements including enriched single housing and monitoring-guided analgesic use are important.