Sweet FBCM Babies Peaslee! I hope I can get mine to hatch. What did you do for humidity? These were the ones from ladycats right?
Just checked my calendar, the ones I have from her should
be due 3/16-17.
50 % is awesome for shipped eggs, let alone FBCM! Way to go!
Yes, they are from Ladycat.
I ran my humidity around 45% and hatched at 60%. I ran it higher than I typically do because the air cells were much bigger than I see on my own eggs.
The chicks that failed to hatch, were fully developed but I think they couldn't move in to the correct position because of the saddle shaped air cells.
I also hatched some of my own BCMs and got 86% hatch on those. Oddly enough my eggs also hatched 2 days before the chicks from Ladycat.
Hens go broody when you don’t want them to… and won’t go broody when you do.
But, now you'll have that experience to help you in the future 
It's like they are going through a .. doogy mutt...stage.