IIRC in the mid season finale, didn't Rick and Carl try to go back for Judith (before Rick got injured) and only found that bloody high chair? So they probably presume she's dead and thus have no reason to ask about her fate.

I didn't see her either. I hope that's not a bad omen.

As for Beth... I heard some speculation that she was the uh, 'meal' on the grill at the end of the episode when the rest of the group got to Terminus.