A rabbit is not a mouse: a framework for the initial welfare assessment and long-term monitoring of genetically altered laboratory rabbits.

Genetically altered (GA) rabbits are used in biomedical research due to their unique physiological and translational relevance. Despite their importance in multiple biomedical research specialties, species-specific guidance for their welfare assessment is limited. This article proposes a comprehensive framework for the initial and long-term welfare evaluation of GA rabbits, covering all life stages from birth to aging. Key indicators and biomarkers include neonatal viability, maternal care, post-weaning growth, sexual maturation, reproductive performance, and late-onset phenotypes, alongside clinical, behavioral, and physiological markers. Emphasis is placed on recording evidence to contextualize observed deviations from wild-type baselines. Accurate monitoring of phases-specific biological biomarkers enables further detection of relevant phenotypes, beyond initial welfare assessment. This framework offers practical guidance for researchers, veterinarians, animal welfare officers and competent authorities, promoting not only non-maleficence but also positive welfare approaches. Implementing a species- and model-specific frame facilitates responsible management of GA rabbits, ensuring ethical integrity, scientific rigor, and the development of positive animal welfare strategies throughout their lifespan.