What movie is it where a guy gets bucket of KFC and eats only the skin?

That sounds like a scene from the 2009 film "The Hangover".

In the movie, Alan Garner (played by Zach Galifianakis) is seen ordering a bucket of KFC and then only eating the skin, leaving the chicken meat untouched.

It's a humorous moment in the film, emphasizing Alan's peculiar and eccentric behavior.