Well, actually, you don't. Perhaps you have powerful transformation magic, and it's transformed goose. (And what else can you transform? Can you turn a walled city into one walled by green cheese? Can you turn fugitives into eggs and carry them out in your basket?) Perhaps you have powerful preservative magic. (And how long ago did you discover that? Do they have such dishes as marmalade, or smoked sausage, or ripened cheese, all discovered in the process of avoiding food going bad?)
Just because we can do it one way doesn't mean a magically based world has to do it that way. Instead of steam ships, they might devise wind control spells for ships. Instead of fountain pens, a way to take the color from the feather -- crow's feather would be best -- and use it to write with.