Stillbirth?

We recently decided to do away with our mouse colony since we haven't had much luck in breeding them (small litters, bad moms, ect) so we fed them all off except two females we are keeping as pets and one female we suspected was pregnant. I refuse to feed of pregnant rodents so we set her up in her own little tub with food, water, and bedding and gave her tissue for a nest. The other day she gave birth to 5 babies, two of which were stillborns. They were warm (mother had been nursing) but limp and not breathing. I doubt she killed them as they had no obvious signs of her attacking them but does anyone know what could have caused those two to die? All remaining babies will be fed off soon enough as well as the mother.

It just happens Jay. With any animal that gives birth, stillborns can just happen. One baby or 20 baby creatures not all are always meant to make it. Some never start breathing either due to a problem with their health or the mother rodent not stimulating them or getting them loose of their birth sac/cord quick enough. Sometimes they aren't strong and the mother animal just knows that and doesn't bother with them at all (letting nature take it's course type of thing). Sometimes it's an inexperienced first time mother whose just overwhelmed in the birthing process and doesn't attend them all quick enough or lays on some while birthing/nursing others. Basically it just sometimes happens.

You may see the mother's kick these dead pinks out of the nest or even eat them (recycling them basically as gross as that sounds for us humans, it makes sense for the rodents). I never worry about stillborns unless it's a high percentage of the litter or happens a lot with a certain female. I don't get many of them but I suspect there are some I just never knew where birthed (the recycling thing).