I am raising my 3rd batch of chicks now, and I use an over-the -brooder radiant heat (ceramic) source only for the first week or two, and switch to an under-the-brooder heat pad that is made for sprouting seeds after they no longer need the 95-90 degree heat. I find they are very comfortable, there are no "cold spots" (I put it under only half the brooder so they have a cooler end if they want), an it uses less energy, since heat rises. I find the bottom heat tends to to dry out the stool and makes the shavings last a longer time. Altogether, I think it is far more efficient than an over-the -brooder heat source. I have never liked the idea of having a light on all the time, thus the ceramic heater, but I like this better . The ceramic disk gets really hot, too, and I always worried that if it fell it might cause a fire or hurt the chicks, no matter how carefully it was set up. I have the chicks in an un-air-conditioned room with an open window(out of the sun), so it is in he high 70's or mid 80's, ambient temperature. The heat pad is about 2 feet long by a foot wide, flat plastic, with wires imbedded in it for heat, and plugs into the wall. It is waterproof. You cannot adjust the heat, but it stays plenty warm without getting so hot it could damage anything, and once it has been on for a few hours, the 2' of shavings in the brooder is nice and toasty. I got mine from Gardener's Supply catalog probably 10 years ago, and they are super for seed sprouting, too! They make a huge difference in sprouting rates. I also switch to a nipple waterer at about the same time I move my chicks to the larger brooder, and hang it from the top of my "second step" brooder, large portable wire-top cage with a solid bottom used for small animals. It has a plastic bottom about 5 inches high, is about 3 feet long and 2 feet across, and the wire cage is about 1.5 feet tall, with a door opening at the top and the side. It's perfect to give chicks a good amount of room to roam. The 2 quart nipple watering device (Avian Aqua Miser) ensures the chicks always have clean water, and it takes only a few minutes for them to catch on once I tap the nipple with a pencil a few times. This set-up is a real time saver, and I feel much safer with it than having a lamp-type device suspended over my chicks.