I'm almost finished with my run and was wondering if anyone out there has ever used mulch for the floor. I've heard about construction sand, shredded leaves, the pine shavings...but never heard anyone say that they use mulch. I have an 8' x 16' run that needs to be filled b/c I put 1/2" hardware cloth across the bottom to keep out rats, so I need to cover it all up with about 4 inches of something and I can get free mulch from the town. I know we shouldn't use cedar and I was told that the mulch is a combo of every kind of tree, so if there is any cedar in it, it won't be much. Thanks!