The fledglings dropped the uncracked horns about 1/3 the time while I worked this quest. Theyre' level 51-53. Took about 30 minutes. Makes sense that the young ones would have uncracked horns I suppose.

You can find them all allong the road into Winterspring from Felwood. I found the highest concentration in teh Frostfire Hotsprings valley area. Watch for bears, yetis and owlbeasts as adds.