Today I am thankful for the inquiry from Andrea Mangoni who contacted me from his home in Italy. He asked for information on Polverara chickens.
He keeps a flock of this rare and very ancient breed. His birds are the ones pictured on http://www.feathersite.com/. This black hen, Nerina, was hatched in Spring 2008.
The breed is related to Brabanters, which have a similar crest but are associated with the Netherlands. The National Geographic of April 1927, which documented many breeds, cites Polveraras as being an ancestor of Polish chickens.
This nugget of information made the name Polish fall into place for me. There's always some discussion as to why the crested breed acquired the name Polish, since it is not associated with Poland. Having a crest on the poll of the head is sometimes advanced as the origin of the name, but being descended from Polveraras makes more sense to me.
Andrea is writing a book on the breed and has a web site, http://www.oryctes.com/gallinapolverara.html, and a blog, http://oryctesblog.blogspot.com/search/label/Polverara, devoted to them.