Nihongami: Hairstyles of the Yuukaku - Tayuu, Shinzo & Kamuro
Historical Time Period: Mid-Edo Period - 2nd Half (1753-1789)
Hairstyle Name: Kottai Niwatori (古体 - 鶏) lit. “Old Style - Rooster”
This is a variation of the kottai kansuzume, which is originally a variation of the kottai wareshinobu. The version pictured above features a hashi-kanzashi, whereas the original kottai kansuzume does not. The primary difference between the kansuzume and niwatori are the name sake birds; kansuzume are winter sparrows, while niwatori are roosters. Both sparrows and roosters have a seasonal association with late winter and new years, so this may have been chosen to invoke the coolness of winter during the heat of summer. I would like to believe, since it is still largely a kottai wareshinobu, that it would still be used by a furisode-shinzo as a special winter version of their more common hairstyle.
Source: https://twitter.com/ayaka8700119/status/1151000520527450113?s=20