Due to recent changes in EU regulations (2010/63/EU) as well as the general requirement to assess the condition of experimental laboratory animals, the development of innovative severity assessment strategies is required. In murine inflammatory bowel disease (IBD) models severity assessment is usually performed by clinical scoring, which is time consuming, stressful for the animals, and necessitates an experienced observer. This mini review looks at methods to identify disturbed animal welfare during experimental colitis by investigating changes in spontaneous animal behavior. We give a brief overview of the existing methods of severity assessment utilized in colitis models, focusing on a recently investigated method, the time to integrate to nest test (TINT). In a study investigating the course of colitis in genetically-susceptible and corresponding wild type mice, the suitability of TINT as a parameter of disturbed welfare was determined. TINT enabled the detection of mouse strain-related differences, but not dextran sulphate sodium (DSS) dose-dependent differences in colitis manifestation. Therefore, TINT may serve as an easily applicable indicator of disturbed animal welfare but cannot replace clinical investigation of animals under experimentation. The development of further severity assessment strategies that better mirror the actual condition of animals used in IBD studies is therefore vital.