I use crushed corncob substrate. The good part is the fact it's very absorbent and keeps any odors down. The bad part is small pieces that can be swallowed. I hand feed all of mine, once they've taken the food I pick them up. Since I have large groups, fights are also an issue. Holding them while they eat stops any fight from ever starting. Corncob also clumps the waste together for easy removal. One other problem with this stuff is the fact it will mold very quickly if it gets wet. It requires daily monitoring.