Go-chan16 said: Could be that they were pregnant and getting the children forcefully aborted or killed for having disobeyed rules. Not sure.
Kinda don't think aborted. Killed..maybe, in a sense. This is supposed to be the Factory, and I'd think the babies are either used for food, experimentation or sold to pet shops.
I also guess these Reimu are for breeding, so they'll be allowed to refresh and temporarily forget the previous pregnancy.
All the yukkuris born here will be consumed as "guinea pigs", and ultimately they belong to only one place: the incinerator."Mister Human! Mister Human!"
Reimu knocked onto the tank window and tried to stop the researcher.The researcher raised his head from the books and ignored Reimu's questions.Little ones! Where are Reimu's little ones?