Bioactive Cages
A bioactive cage provides a “self-cleaning” ecosystem that breaks down animal waste and provides a more natural environment for them. It should include a clean up crew of Isopods and Springtails, and your rats may even eat some of the clean up crew if so inclined (this is perfectly safe, and it is a fun healthy snack for your rat).
Substrate
A good substrate base for a bioactive cage is coconut fibers/soil. These hold moisture well and provide a living base for the bugs and microorganisms that will provide the ecosystem that breaks everything down. You will still need to do spot cleans and you may need to turn the soil to mix everything in, but the substrate should be generally self-cleaning and a lot less smelly than traditional bedding options.
Clean up Crew
Your bioactive cage should include a generous amount of Isopods and Springtails. The Isopods will break down large organic matter (waste, spilled food) and the Springtails continue that by breaking down what the Isopods leave behind. These bugs will require a moist/damp substrate layer to live, and they enjoy hiding underneath things. Try including cork bark (you can see some blue Isopods climbing on the bottom of the bark in the above picture.
