These babes are about 16-18 weeks old. I didn’t notice this on any of my hens so was curious. They have such long wing feathers. I believe they’re all coming out. Why are they so long and when their “adult” feathers grow in, Will they also be so long?
Those are primaries and not exceptionally long. Sometimes as feathers are replaced, especially in chickens approaching maturity, the secondaries that normally cover the primaries are not in place exposing the primaries making them appear particularly obvious like you are seeing now. They will retain current length as covered later.