The day I got my chicks I forgot to put paper towels over the pine shavings at first and then I realized that although the chicks would occasionally pick up a piece, they spit em back out. I'm using large flake shavings besides and they just don't seem interested in eating them.
Your chick is older. Perhaps she's bored? They naturally like to peck at things looking for something yummy to eat. Do you give her treats? Try some cheerios, some greens, or perhaps a nice, fat, juicy worm if you can find one. Remember though, when you start the treats you also have to start giving grit, unless you're providing that already.