This presentation will discuss the properties of beddings on the market today and why the use of bedding alone does not promote thermoregulation. Topics included will be the importance of bedding properties and how they perform within the micro cage environment. Thermoregulation behaviors will be discussed as well as abnormal behaviors from lack of thermoregulation. The importance of using a "system or program" of bedding and nesting materials as a means to improve thermoregulation will be explored. Combining base bedding with the addition of nesting material options creates a portion controlled, repeatable system that is not only natural for mice, but also reduces rodent stress, facilitates study accuracy, and provides efficiency in today's laboratory. Topics to be covered include the benefits of having nesting materials as well as the abnormal rodent behaviors associated with today's lab environment and how they impact thermoregulation. These "unnatural" behaviors can all be reduced or eliminated through proper use of bedding and nesting system or program that promotes and allows for thermoregulation. Also discussed will be the benefits and reduced vivarium management costs of using a bedding and nesting program which is of value to the individual investigator as well as the importance of having a bedding and nesting program for animal welfare.