"Chicken Little" takes the simplistic fable and twist it into WWII propaganda warning against the rise of Nazism. A funny cartoon could have been made of these elements, or even a reasonably entertaining one. But "Chicken Little" is loaded with problems.
Cheap animation is surely one of them. The mouth movements and vocals don't sync up fairly often. This is mainly a problem with the various barnyard denizens, but in the very last scene Foxy Loxy's mouth and voice aren't even remotely working together to make something believable.
Another is the distinct lack of jokes. Chicken Little's gullibility isn't very funny, nor is the mass hysteria that sweeps through the hen house. In fact, it's all played a little too straight yet animated as if we were supposed to be charmed and laughing at the physicality of it all. But none of it is really all that funny.
I will give this cartoon some kudos for its bleak ending. I'm surprised Uncle Walt would even allow for something so dark and depressing to be the ending to one of his cartoons. It's morbid, but it's also one of the few truly hilarious gags in the whole film. Which isn't really saying all that much.