Shawn, I have had a similar situation multiple times and figured out a couple problems. First when restoring body body heat, be careful with hair dryer, that air is very hot and damaging especially as fuzz / feathers dry. Our skin is much tougher than chicks. I have learned getting core temperature up can be done faster with warm water under sink. Make flowing water at or just below targeted temperature. Takes a couple of minutes of exposure to recover core temperature. Obviously be carefull not to drown. Once core temperature / mobility / mental state restored, place chicks into dry brooder where they can controll exposure to heat source. Mobility key to rapid return to normal activity as they can regulate core temperature impart by moving in respect to heat source and preen. With larger chicks. the incubator can be a killer since they can not thermal regulate down. If they are alive, their metabolism heats in addition to ambient conditions of incubator. If incubator to be used, then remove as soon as heat heat stress evident (panting). I think damage with heat stress hits brain first.