Foxborn. Foxborn Trilogy, #1

On a primitive world where adults can morph into the totem animal of their tribes, a young fox born girl must complete the initiation rite into adulthood and lead her ritemates and Fox Clan in a war against the wolf tribe, the Wolfen. She and her twin sister form an uneasy alliance with the uninitiated children of other clans seeking a way to complete the initiation rite and save their younger siblings and their way of life.
Forced into an unexpected role as the leader of the ragtag team of survivors from the Wolfen attacks, she has to guide them in their fight for survival or die trying.