Awe... so cute. Not necessary but you may want to consider a very light shadow cast for the bills. This works fine, I'm just thinking about a little tweaking. LOVE the color enhancement/matching colors/feathers of the skin. You may want to shape the head of the 4th duck, it has some obvious cut/erase marks that draw the eye to them. The first duck head has some shape issues but not as noticeable. Duck heads are very very ROUND and any kind of disruption to the curve creates distraction. Really is a great idea for a very very hard source image. Too much subject matter and you handled it brilliantly.