This is a great film that isn't necessarily inappropriate, but the story it tells isn't one that your child will enjoy. Really, the best age to watch it is around 15 yrs, albeit that is for more sensitive and compassionate children. The lowest would probably be about 13.
Spoiler Warning This was a fantastic movie. The protagonist becomes a villain and his nemesis/surrogate father was the only character with a sense of honor. On one hand the Wolf killed the lamb's mother and he went to take vengeance. On the other hand, the wolf was doing what he needed to survive but raised the lamb anyway, and the lamb became a very brutal murderer of other animals including the guardian dogs of his old flock.
Spoiler Warning This was a fantastic movie. The protagonist becomes a villain and his nemesis/surrogate father was the only character with a sense of honor. On one hand the Wolf killed the lamb's mother and he went to take vengeance. On the other hand, the wolf was doing what he needed to survive but raised the lamb anyway, and the lamb became a very brutal murderer of other animals including the guardian dogs of his old flock.