Okay, this one had me hunting through picture-book memories for a while — there isn’t a widely known children’s or middle-grade book where the protagonist is a princess who deliberately disguises herself as a turkey. What most people recall with a turkey-disguise premise is the very charming picture book 'Turkey Trouble', where the turkey is the one putting on disguises (cow, pig, etc.) to avoid
Becoming Thanksgiving dinner. That book’s premise is a turkey trying on costumes, not a royal in feathers, and that mix-up happens a lot when stories blur together in the brain.
If you’re specifically remembering a princess in a fowl costume, my best guess is you’ve conflated two different stories — a princess-disguise tale plus a turkey-disguise tale. For the princess-disguise side, classic and modern examples include 'The Goose Girl' (a princess forced into a lowly role and hiding her identity), 'The Paper Bag Princess' (who upends princess tropes in a delightfully pragmatic way), and the spirited heroine-in-disguise vibe of '
Dealing with Dragons'. For the turkey-in-disguise vibe, again, check 'Turkey Trouble'. Libraries and bookstore listings often tag these with keywords like "disguise," "princess," or "Thanksgiving," which helps when memories are fuzzy.
If you want, I love digging through children’s sections and can recommend a few picture books and retellings that blend royal characters with animal antics — they scratch that same itch even if the bird-costume-princess combo is rare. Personally, the image of a princess trying to waddle stealthily in feathers makes me laugh every time — such a great scene for a picture-book illustrator to have fun with.