Hi :wave: What are you using in the litter trays? I use wood pellet cat litter in mine and have hay in racks above the tray. I've never noticed them eating it, they don't even eat the hay once its fallen into the tray lol! I know a lot of people use newspaper and hay only, or other paper based litter. As long as the litter material is "edible" and won't swell up inside them it shouldn't matter, depending on how much they are eating of course... It might be wise for you to change to using newspaper with hay on top if they are insisting on eating the litter, if you aren't doing this already. Do they get loads of hay too, they might be hungry?