I use indented kraft paper from Uline. I love it. It is really nice thickness and it has dimples in in that help absorb messes. I order it on line by the roll. I get the 2 ft wide by 320 foot roll. It cost me $29 but it last a long time. I use it for three 4 foot AP cages.

https://www.uline.com/BL_1961/Indent...ulinepaperwrap