I'm with Cree on this and I don't even start checking until 6 months old.
And I wouldn't expect split wing to effect their flying ability really.

My breeders are the only birds I ever check for it. So far, NOBODY has any problem making it up and over my 4 foot fence IF they choose to. 2.5 feet is nothing to a bird... except maybe a Silkie!

Most my high roosts are higher than that but have a ramp. And I have a lower roost (under the droppings board) where younger birds usually start their way into the pecking order.
Awesome that you are looking out for faults!

I would expect sprigs to show up first, maybe. But give the wings a chance still if the bird is young as you say.
ETA: especially since you think it's both, they probably just haven't grown in yet.

Never had a split wing show up yet... though I only check the ones I'm keeping.