Hobb, Robin. Rain Wilds chronicles #1

Guided by the great blue dragon Tintaglia, a tangle of serpents fights its way up the Rain Wild River to the cocooning grounds. But the creatures which emerge from the cocoons are a travesty of the powerful, shining dragons of old; some cannot fly, others are stunted or deformed. To save the dragons, a band of dragon keepers, hunters and chroniclers must attend them if they are to find their true home--the legendary Elderling city of Kelsingra