A decent enough photo, but in a free study, you need to really have it POP! This is just a straight down, centered shot. Try other angles, other compositions, off center perhaps.
Very cooperative subject aren't they? :) Couple of things holding this back (beside subject matter); composition is too centered, nothing unique about the arrangement (looks like a snapshot), could use a little more contrast, and the bg is very busy (read distracting). All JMO of course. :P Good luck in the challenge.