Shoebill Stork

My 11-year-old is in the process of writing a book about weird animals. He's enlisted me to do all the illustration for him. Here's my first pass at the Shoebill Stork. I'm using this as a style test for the rest of the aniamls. I'm not 100% sold yet, so I welcome any thoughts. The biggest thing I'm questioning is the texture. I'm not sure if I should leave it or do something that's more flat.