You want to make that "not possible". Chicks can get stuck between the pad and frame and die.
That is too many to lose (any is too many but 25%!!). How did they get smooshed? Is the cave big enough for all with the ability to get out from both the front and back?
I'm not sure why they are dying. The cave is plenty big, and they can get out of both ends. I put 7 that were VERY small compared to the others in a separate brooder with my EcoGlow so that they didn't keep getting run over, and I they seem to get weak, and then weaker, and then I find them dead in the morning. Not all squished, but laid over on their sides and dead in the morning.
I've never lost so many chicks before, but I've never ordered from a hatchery either. I've always had good luck with chicks, so i'm not sure what's wrong now. I have to think it's the health of the chicks, since I've brooded tons before and never lost this many.
Most of the ones that have died have been in the other brooder, so i'm not concerned that it is from anything related to MHP. I separate them when they seem weaker. If that makes sense.