Here there be spoilers if you haven’t seen the film…
Apparently Disney struggled with What To Do With The Chicken.
He turns out to be a hilarious punchline throughout the film.
He also provides someone for Moana to talk to rather than being alone on a boat and talking to herself, or doing silly Exposition in Dialog.
But is he more?
In the end, he does one Very Useful Thing, saving the heart of TaFiti from falling overboard, and allowing Moana to put it back safely in her necklace before she ultimately restores it to TaFiti.
Nice, but… something else?
Innocuous fools have often enjoyed special privileges in cultural and economic groups, whereas aggressive madmen have had to be restrained or incarcerated. A fool’s powerlessness and helplessness may gain him or her protection of more fortunate people. Since the fool is only guided by his natural instincts, because he or she does not understand social conventions, he or she is not culpable for breaches of those rules. The fool is not expected to “know better” or “know” anything.
Another aspect of the wise fool may be shown in his or her rejection of the norms of the culture in which he or she lives, if he or she deems those norms to be counterproductive. (wiki)
Moana supports and loves her culture/people/family, but she also rejects some of the norms; breaking the taboo against voyaging beyond the reef (aaaaand, navigators were, till now, usually male). The chicken reflects this part of her on some level. After all, he stowed away.
The wise fool is often a jester or sacred clown, his goal is to enjoy life as it is.
A lack of concern about what other people think of them.
Trusting the process – enjoying the journey and letting things be rather than trying to control them.
Living in the present moment – because that is all there is.
Living life as a game – seeing the lighter side of darker situations.
They poke fun at the ego.
They create their own rules.
No matter what, the Fool has a zest for life!