When birds like chickens and ducks are young, they must stay warm and safe. Their mother usually takes care of this by keeping them in the nest and warming them herself. When she's not available, people must substitute artificial heat in the form of an incubator for the chicks.
Put a hole in one side of your cooler, 3 inches from the top edge. This hole is for your lighting mechanism. Put three more holes in the cooler, along another side, 3 inches from the bottom. These are circulation holes. Make these bottom holes small enough that baby birds won't try to crawl through them.2
Take the wiring, extension tube and any lightbulbs out of your lamp-building kit (available at home improvement shops). Slide the extension tube through the hole you made for it so that the lightbulb end is inside the cooler and the wiring end is outside. Screw in the lightbulb.3
Place your thermostat inside the cooler, in one of the bottom corners, where it can measure the cooler's internal temperature. Attach one of the lamp's power wires to the thermostat, per the directions that came with your lamp-building kit. Attach the other lamp wire to the plug that came with the kit, but do not plug it in yet. Attach the thermostat's wire to the plug, again per the lamp kit's directions. Your thermostat will now monitor the temperature and lamp power.4
Put shavings or straw in the bottom of the cooler, at a depth of 2 to 3 inches, for the baby birds, and set out a water dish. Put the incubator in a safe place, out of drafts, and confer with a local livestock and poultry store about the ideal food and temperature for the birds you're raising. Every bird has different needs in regard to temperature, food, water and humidity.