I'm assuming from what the ko on the right is saying, that the squashed ko had a birth defect. Buuut it looks like the squashed one is a normal one, while the unsquashed one is the one with the defect.
Perhaps its about to receive the same, and just doesn't realize it yet?
Man, all the yukkuri abuse pics are getting to me because I immediately assumed that mother Reimu was being stupid and forgot which one of her babies had the defect. I figured that the squashed one's right eye was under a tuft of hair.