I'm really trying to find out the name of this movie I only remember one scene right now. Its about some sort of animals and there are more animals and one of them is stuck in the mud they end up getting him out and then they sing this song like a gospel song about how he's free and I think it may have robin williams voice in it but I'm not sure

It's "Rock-a-doodle"

Oooh I know this one... One upon a forest, definitely!

Once opon a forest. It was a nerdy bird stuck in mudd haha