If you can see air, it probably needs to belch, for lack of a better term. When I handfeed cage birds, this sometimes happens. Unless the crop is grossly distended, you generally can leave it alone. You can mechanically burp your chick by very gently extending the neck - beak should point up at a 45 degree angle, neck should be straight up and down. Then very, very gently massage the crop. Do. Not. Force. Or squeeze.
Disclaimer: I have never needed to burp a chicken chick, this is the proceedure for parrots, finches & canaries.