I put five chicks in a 20gal aquarium with a mesh lid for the first two weeks. Then I moved on to a big rubbermaid. It worked great--and actually was too cool initially, so I had to raise the floor by putting Yesterdays News underneath some puppy pee pads. That was only for the first week, then I moved them onto the floor with the pee pads. Once they moved into the larger bin I just stuck with the yesterdays news. It worked great!