Congrats on the little cuties!
We ran into the same issue a few months ago too and it really sucked!! I think we lost 4-6 really good girls.
Do you have any idea what was causing it?
The only thing I could come up with was thru a friend who thought it might of been breached babies, but that it happened in a short period of time maybe over 2 months and we hadn't had any issues before and none since is kind of weird to me.