Bonnie

The Henry VIII letter can be seen, with transcription, at Luminarium Anthology of English Literature (click the image to get a larger, readable, version).

I haven't been able to find how widespread the term duckys for breast was. Mark Morton's book The Lover's Tongue (A Merry Romp Through the Language of Love and Sex) has "The word duckys might simply have been inspired by a resemblance between the soft, white feathers of a domestic duck and the soft, white skin of an English woman's breasts, facilitated by the coincidental resemblance of duck and dug, the latter denoting an animal's teat." Partridge doesn't mention it in this sense.

Now I'm stuck with the earworm!

Mick