Hello and welcome.
I suggest you check out this thread, it's huge but the first couple pages will get you started.
The upshot is that the temps in the brooder are not that important, in fact they can be very cold (think outside in WY in spring). What the chicks do need is a warm spot to go to so they can sleep or warm up in between adventures. I am currently using this system, my chicks have been outside since day 2 and they're doing great one at 4weeks old.
Of course, different people will have different opinions so you will have to go with whatever makes you comfortable.
http://www.backyardchickens.com/t/956958/mama-heating-pad-in-the-brooder-picture-heavy-updateEdited by WVForestGirl - 3/25/16 at 4:45am