Sorry for you losses, that sucks. I would think if your room is sixties to seventies, you would need a additional heating. Up to the mid ninties would be good.
I have my hatchlings together at the moment and they are doing great and interacting well. But time will tell.
Could you show pics of the devise that crushed your neonates. That could benefit others who may try the same thing. I cannot even picture how it happened. Best wishes