This may seem a dumb question but it is driving me crazy! I have been under the assmption that the feathers I buy at the local archery shop are some type of man made feather ( I am not confusing feathers and vains) but nothing I read mentions any synthetic feathers. They come in a thousand colors and they feel almost plastic rather than nataural feather feel. Are all feather fletches natural? Also the bit of foam material on the quill made me think "man made".
The quill of the feather has a hard keratin lyer over a pulpy core-this inner material is what you are comparing to "foam" and its pretty analogous to synthetic styrofoam. I've seen molded vanes in the past that were textured to resemble real feathers but to my knowledge no one has developed a process to replicate the real deal. Feathers are pretty incredible examples of engineering-the colors are created with dye. Google them up-you'll be impressed. Grant