@resilientinuk: First let me say, all feathers are special. They are all unique in their own way and are gifts from the Creator. These parallel lines are found in many game birds and not in an eagle feather. Sometimes you need a magnify glass to see these lines. It starts at the base. The groove in a turkey feather is "U" shaped and in a eagle feather its "v" shaped. #eaglefeather #turkeyfeather #learnwithme