You rang? Here I is.
Heat lamps. If you're going to be using one, the best thing to do is to calibrate it to the right height for the proper temperature before the chicks arrive.
Get a thermometer and lay it down on the brooder floor on top of the bedding right under the heat lamp. The heat lamp should be at the far side of as large a brooder as you can find. The chicks will need a large cool space to shed excess heat. Move the lamp up or down until it reads 90F. That's a good starting point. This is the only time you will need to use a thermometer. From this point on, your chicks are the thermometer.
When you get the chicks installed, watch their behavior. If they are all huddled right under the lamp, move it a tad lower. If they're all hanging out at the far fringes and not spending much time under the lamp, then they want it cooler. Move the lamp up until you see the chicks covering the whole brooder with their activity.
Keep in mind, for all practical purposes, you are weaning your chicks off heat from the first week. Your goal is to get them feathered out and off the heat lamp by the end of their fourth week. In order for this to happen, you need to keep the heat to the minimum that the chicks require to be comfortable, reducing it gradually every few days by raising the lamp or swapping the 250 watt bulb for a 100 watter. Let the chicks' behavior be your guide as to what is needed but keep making it gradually cooler.
In conjunction with this program of heat reduction and weaning, it's very beneficial to bring the chicks outdoors for play time beginning at the end of their second week. Choose nice, calm days for these outings, watching the chicks for signs of chilling, and returning them to their brooder when you see it.
Gradually extend these outings so that by age three weeks, they are spending several hours outdoors. By age four weeks, they may be spending all day outside without any heat source. By age five weeks, they can be sleeping in their coop with no heat.
That's how I did it. But now it's so simple and easy to just brood them outdoors to begin with, and they acclimatize in place. No fuss. No bother.