Huh, you might be right, it's been a fair while since I've played this one, but I assumed that you only keep the children of the broodmother. The children of the rest of the herd get released to the wild...figured the mechanic was in place to slow down animal broods but never really thought about it or whether it was just a bug or simplified systems. Guess the way to check is to pay attention to the timers or dive into the code.I think it's just a bug, frankly. As far as I've noticed, any monster girl can give birth (except with the Bee Girls) but when one does it resets the pregnancy status of all the other ones, as if she was giving birth on behalf of all of them. I think there's only a single pregnancy timer for each group of monster girls which they all share.