Hmmm I've never seen anything like that
It doesn't look painful or irritated, just like it grew in wrong. Maybe he pinched it or damaged it early on when it was growing in?
It is more like someone put something in the straw that was too big for it and it stretched the straw out. I would rather leave it but Iam worried that it could be infected or get infectedI guess I don't understand why it needs to come out. It looks to me like he has sort of split the shaft of the feather at one time but as it is healed ( or was not a blood feather when damaged) and no longer a danger to the bird ....why does it need to come out? To me it kinda looks like if you take a straw and bend it ...it slits along the length.