I read about the temperature guide to keep chicks warm in a brooder.....95 degrees the first week, etc.
My method is a bit different. I "listen" to what the chicks are telling me.
I place the heat lamp on one side of the brooder. If the chicks huddle for warmth or all stand under the heat lamp, I increase the temperature.
If they stay away from it, it's too hot.
What I want to see is chicks sleeping under the heat lamp with space between each chick, not a huddle of sleeping chicks.
When chicks get too warm, they will move themselves away from the heat. When you see that no one is spending time under the heatlamp, it's time to raise it.
Always make sure that your chicks can get away from the heat. And they will "tell" you how much heat they need and when you can wean it.
It's not always a matter of 95 degrees the first week, 90 degrees the 2nd week, etc. The chicks will show you what they need. You will find that they wean themselves faster as well.