In the Book
In the Movie
This doesn't happen.
Radagast distracts a herd of goblins that are chasing the adventuring group.
Bilbo sees a group of trolls and decides to sneak up on them so he can pickpocket them.
He goes after the goblins because they have stolen the ponies for food and he wants to save them.
Bilbo claims a large knife in the trolls cave and names it Sting.
Bilbo is given the sword/knife by Gandalf.
Smaug doesn't appear until the end of the novel.
His scales are shown as he speaks in the prologue and the ending.
The company's ponies are taken by trolls and eaten.
The ponies disappear when the bolt away together.