The last thing that happens before they escape the egg is the abdomen closes up and depending on how long elapsed between that moment and the chick kicking free of the egg, it might just be that it's very delicately sealed, like a pastry with filling that isn't baked. If there's debris it's possible you might be seeing (hard to tell) is the poop sac that isn't always disconnected at hatch, where all the waste goes during development - if that's still connected it looks like a mucus string when fresh and can almost resemble a thread once dried- that can be safely snipped. A good spray with vetricyn if you're worried, or a dip into a betadine solution won't hurt. A closer picture of the navel (just below the vent) might be informative.
If the loud chirps continue, do have a look at the feet and make sure she doesn't have curled toes - way too early to be sure of that, but sustained chirping can be a sign of discomfort when combined with curled toes. Easy enough to make up a chick shoe and vetwrap it on to help the toes straighten out.
Thanks for the advice!
