I had some I have hatched do that, took them to the State Vet for Necropsy. We have a lot of hatcheries here for meat birds , the State Vet calls them "Starve Outs" , what it is and I hope this does not start a flame fest, Hatcheries of course make money by the amount of chicks they sell, so they hatch every egg. In nature not all eggs hatch, but when you artificially incubate eggs that would not have hatched will hatch. So in essence the chicks that are not thriving likely should not have been hatched.
I have nursed some and gotten up the be several months old only to still have them die.
Oh and before anyone questions our State Vet here, he has been a vet for almost 50 years, I trust him.
IF you think about it, how many times in the hatching thread do people say , not to help with hatching. I have done it, and a lot of times those chicks I helped ended up dying a few days or weeks later as starve outs. When you necropsy these chicks they will probably have no food in their intestines, maybe a little bedding but no food.