Even with grid floors and adequate ventilation the cage temperatures may be 3-6OC above room temperature. The difference is likely to be greater in the solid-floored cages used for breeding. Provision of bedding or nesting material allows the animal an opportunity to manipulate its own immediate environments, and provide a warm nest for its young. This may also promote greater utilisation of the available space. Relative Humidity 4.4.
Humidity control is an important consideration for laboratory rodents.
Specific air change rates in the room are less important than ensuring that there is an efficient flow within the rooms to keep the level of ammonia within the animals' immediate environment at an acceptable level. Light levels within cages are more important to the welfare of breeding rats, mice and hamsters than the light level in the room. Lighting intensity should be that only which is required by husbandry practices or safety reasons. The importance of light to dark cycles in regulating circadian rhythms and stimulating and synchronising breeding cycles is well documented. Animals, especially when breeding, should be given the opportunity to withdraw to shaded areas within the cage, for example by provision of adequate nesting materials.