I use a large tub. I found that hooking the lamp on the back of a chair I can move it away from the tub so it doesn't get too hot. That way it doesn't heat up the whole tub and gives the girls somewhere to get away from the heat. I plan on making a mother heating pad set up. I also have the water on a rack over a pie pan to keep pine shavings out.
I also was having a problem with the chicks roosting on top of the water and feed then pooping in it. To stop this I cut a circle and a strip of cardboard long enough to wrap around the top of the jar and then an extra inch or two. I cut a slit to the center of the circle and make a cone out of it. I taped the strip to fit around the bottom of the jar then taped this to the cone by cut slits into the strip and bending them.