What are they in now? When I move mine from the incubator, I have the brooder set up with paper towels under shelf liner. I leave them on that for the first day to get all the toes and legs nice and strong. After that I remove the shelf liner and paper towels and I put them on pine chips. If you have earlier chicks in your brooder and don’t want to disturb them too much, you can just put the shelf liner over whatever bedding you’re using, and take it off after a day. I put my shelf liner in the wash, so I don’t like it to have chips glued to it with hardened poo, so I put it over paper towels.