At the bottom, you just cut out a little opening for them to get in and out, but leave the bottom there. The top of the barrels have 2 holes already there, so take your heat lamp and run the wire up through it so you can plug it in. To hold your heat lamp in place, wrap the wire around a big bolt or something long enough to go over the top of the hold so the lamp won't fall down. Voila.... instant incubator! We put some straw in the bottom to make it comfy and to help hold their heat.
Can also be used in warmer climates with a regular 40 watt light bulb