Circa late 1960’s – mid 1970’s I’d guess. I don’t recall if there are any other similarities to the unknown work in question and Disney’s “The Legend of the Boy and the Eagle”, but just like in the ending scenes of the Disney short, a boy (Native American I think) is pursued and captured by other boys who mean him harm. But, rather than having eagle wings strapped onto his arms (like in the Disney piece), the boy has individual feathers inserted under his skin by his assailants. This is what I recall most vividly – the brutality of witnessing feather shafts poked into the boys flesh. Then the boy triumphantly spreads his new wings and flies off a cliff.