100* is too hot. the temp directly under the heat lamp, at the level of the chicks should be 90 - 95*. You don't need to worry about the humidity. The temp at the opposite end of the brooder should be what ever your current home temperature is. You can provide those lower temps that are so very important by providing a nice big brooder. By the time they are 2 - 3 weeks old, they should have 2 s.f. of open space in the brooder PER CHICK. You can also use a lower watt bulb, and raise the heat lamp higher.
If the chicks are huddling together and yelling loudly, they may be cold. Any time you see a chick panting, you have a crisis of overheating on your hands. An overheated chick can not cool herself off, and will die if you do not provide the cooler temps they need.