Rodney Ho of AJC has the story here
Apparently her 11th place ranking in 25-54 middays didn't help matters (vs. 7th place overall for the station)
along with a 6th place ranking in 18-34 vs. 2nd in mornings and 3rd in afternoons.
I personally thought she fit in great and did a terrific job. Midday is a music-intensive daypart, and I doubt Brittany had much to do with middays underperforming the rest of the station. The music mix might have had a little more to do with it. Of course, music driving the daypart is a reason why a lower-cost talent or voice tracking might work just as well.