Mary Isbister 2008 say Shetland hens are also on the critical list.
Their research points to there having been two types. The first type was a bantam-sized hen, predominantly black in colour, which laid a small white egg.
They found the last remnants of these hens on Papa Stour, a small island just west of Mainland Shetland. The second old Shetland hen is larger and has a tappet head (tufts of feathers on the top of the head). Mary Isbister says these hens are known as "galleon hens" in Shetland. Many of the islanders believe they arrived in Shetland following the wreck of two Spanish galleons which were involved in the failed Armada in 1588.
http://www.burlandcrofttrail.co.uk/page_1150320.htmlhttp://asselbychucks.webs.com/shetlands.htm