The base of the feathers do, "Feathers are known to contain amplifiable DNA at their base (calamus) and have provided an important genetic source from museum sp

The base of the feathers do, "Feathers are known to contain amplifiable DNA at their base (calamus) and have provided an important genetic source from museum specimens." https://royalsocietypublishing.org/doi/10.1098/rspb.2009.0755 https://royalsocietypublishing.org/doi/10.1098/rspb.2009.075... There are also museum specimens, but as you can imagine, way less diverse genetic material can be gathered from those collections.