Thanks everyone for chiming in. I didn't really have plans on breeding mice for feeders, in fact in the future I was thinking rats would be easier and the comments posted here seem to support that. I've been mostly feeding f/t but having recently run into a few new hatchlings that were insisting on only live mice I grabbed extras for the others as well. It was the breeders idea for me to take a few pregnant mice, I was actually reluctant and now I wish I hadn't. I don't think she died giving birth as there were no signs of this but she may have died from complications related to the pending birth.