Haasle, I realized I gave you some bad advice in my post, my prejudice is showing. You do not absolutely have to have cool and warm spots in your brooder. For different reasons I think it is best to have different temperatures, if you are brooding outdoors I think it is essential, but if you are brooding where the temperature is constant you really don’t have to.
The chicks do have a temperature range they can thrive in. As they get older that range widens tremendously, especially on the cooler side. Too warm is dangerous, there is an upper limit on that, but they quickly are able to handle cooler temperatures. As long as their actions show they are comfortable, they are comfortable. How your chicks act is the best guide to how you are doing on temperature.
The chicks do have a temperature range they can thrive in. As they get older that range widens tremendously, especially on the cooler side. Too warm is dangerous, there is an upper limit on that, but they quickly are able to handle cooler temperatures. As long as their actions show they are comfortable, they are comfortable. How your chicks act is the best guide to how you are doing on temperature.