My July 23, 2012 post described how I used wild rice for a painted rock hedgehog's quills.
Another idea is to use pine needles for the quills.
Brush a generous amount of tacky glue around the middle of the rock and press dry
pine needles in it. The needles should point toward the tail of the
hedgehog. Glue a second row of needles in front of the first, leaving a
blank space for painting on the face.