All bedding does is absorb urine and odors and provide a comfy soft material to sleep on. Bedding doesn't allow for burrowing unless it's at least 6 inches deep. It's not necessary and some rats may not care for it. Fleece with an inner absorbent liner works for many people. Just clean the cage regularly to keep everything clean and urine and other odors down.
Crinkle paper is great for burrowing and nesting. I do a combo of crinkle paper mixed with bedding and also have fleece liners.
Crinkle paper is great for burrowing and nesting. I do a combo of crinkle paper mixed with bedding and also have fleece liners.