We use a variety of things here depending on the mood when we are changing the hutch:lol:
Megasorb
Excel Bedown
Bed O linum (have to say this is fab)
No hutches, but a temp bun here has sore hocks. On your thread about sore hocks someone suggested a quilt - & it seems to be working There's rubber matting underneath then quilt, then hay. I would quite like to sleep there myself
Is carpet bad?
Not necessarily. For a healthy, good weight rabbit it shouldn't cause to much probs. But in breed like rexes who have very few guard hairs on the hocks, overweight bunnies or those that have a previous history of sore hocks it can be quite abrasive.