For little ones I used dog potty pads on the bottom paper towels on top of that. Moved them into pine shavings as soon as they understood what their food was. Pine shavings seem very clean and easy to pick out poop.I used old baby nappies. When they’re dirty they go in nappy San soak, and then rinse and wash.
chicks get excellent grip on them. So their legs don’t slide apart.