If you have a heat source for the brooder that also emits light, it will keep the chicks from sleeping all night. This means they will also want to eat as long as they're awake.
I find it advantageous to have a heat source that doesn't emit light, and the chicks thus get a natural break, cutting down on the stress level, which can be considerable in a large brood such as you have. It also serves to get them into a solid day/night pattern early on.
There are alternatives to the traditional heat lamp involving heating pads draped over wire frames to form "chick caves". It sort of replicates a broody hen and the chicks snuggle underneath for warmth, which can get up to 90F inside. There are threads on this forum discussing this method if it sounds interesting to you.