A lot depends on where you're keeping them Maxx. If outdoors, (i.e. outdoor coop, barn, unheated garage) a good rule of thumb is this: If the chicks seem to stay huddled directly under the lamp, chances are good that the temps beyond the sphere of influence of the lamp are too cold for their liking.
If the chicks are scattered about and acting lively, then the chances are good that the temps are just right. In that case, leave the lamp just as it is.
If however, they appear to be trying to avoid the lamp, are lethargic, and spend a great deal of time with their beaks open, then it's very likely that the temps are too high. If this is the case, back the lamp away a bit (suspend it higher above the brooder) and monitor closely.
When brooding chicks outdoors, temps can change drastically and suddenly, so close monitoring is your best friend.
I can't recall with any certainty at what age chicks begin to be able to regulate their own body temperature Maxx. That sounds like a really good question for someone like Speckledhen or maybe Cetawin. Katy could probably answer that better for you too.
We haven't seen pics of them in a while. How about some visual updates?