I had to switch out of using fleece for this exact reason
. I really like fleece for my pigs, but the mess is TOO much, I was having to wash their feet at least once a week because their feet would become covered in dried poop that they stepped on while still mushy. I use Pine now and the problem is gone....it's just a bummer than my piggies can't have the benefit of the soft fleece anymore because of the smooshy poop.