Sorry, I don't believe in the "survival of the fittest" thing, normally. With chicks dying shortly after hatching and being chilled is usually human error, not natures. Were they totally dried before transferring them to the brooder? Depending on the distance between light and chicks I would use at least a 150w bulb. And I personally dip chicks beak in electrolyte water instead of plain water when putting them in the brooder. It's a tiring job, pipping and zipping and all.

no raising/lowering the lamp with a dimmable dial.
