How about the float test?? I've only read about it but seems like a better solution than cracking one open maybe???? I'm hoping an experienced person can tell you just how to do it!
Oh no! I'm so sorry! I'm on my first try now and will cry if none hatch. I think I've read with the still air temp should be 101.5 so maybe your temp was a little low and they're just slow???? Maybe hopefully! I'll keep my fingers crossed for you that all hope is not lost. Good luck!!