Monitoring the welfare of each individual animal in the course of the experiment requires routine daily check-ups, adequate assessment of all aspects of animal welfare, and a reporting system. Of particular importance are the critical phases in the experiment during which the animal’s welfare may be at risk. Ideally, these critical phases should be identified at the start of the experiment. Conducting a pilot study may be useful. Animals whose welfare can be expected to deteriorate, should be examined more frequently and more thoroughly.

Thorough assessment may include undisturbed observation, assessing the response to external stimuli and growth monitoring. Score sheets can be used to record the findings.