Gordon Corera wrote a good book covering their use in WWII: https://www.goodreads.com/book/show/37933332-secret-pigeon-service https://www.goodreads.com/book/sh

Gordon Corera wrote a good book covering their use in WWII: https://www.goodreads.com/book/show/37933332-secret-pigeon-service https://www.goodreads.com/book/show/37933332-secret-pigeon-s...