You truly think flight feathers could “serve zero purpose” if they weren’t on wings? I find it surprising with how much certainty some of you write about a subject that’s so complex and largely theoretical. This mutation could have emerged first as an exaptation, and through sexual selection become more prominent in the population. Also, it stands to reason that “flight” feathers, before the era of flight, could have still served to provide increased running speed and jump height, assisting the avoidance predators as well as the capture of prey.
Does a wild bear poop in the woods? Is the sky blue in the aytime?? Is the Pope a Catholic........