Decided to doodle some moa. As they only became extinct rather recently, we have a plethora of specimens, including mummified remains of skin and feathers. And from these three, we have details from their necks and/or heads.
From the upland moa (Megalapteryx didinus) two complete heads are known. These are excuisite, and with a complete foot, a whole leg, feathers and more, we have a pretty good understanding of what it was like. The Bush moa ( Anomalopteryx didiformis) has one mummified skeleton with a well-preserved head and beak, and from the Eastern moa (Emeus crassus) a piece of neck skin is known, revealing it had at least a partially bald neck and head, not unlike that of the Emu or Cassowary. From these excuisite specimens one can get a glimpse of Moa diversity.
This also includes a tip for palaeoillustration: before breathing the life into your illustration, drawing the specimens is a good idea, as it lets one observe the structure of the subject in detail. Also, I have a feeling one of these was the first birds the Moa-keeper brought back. The Upland moa, perhaps.