Tipping a bird upside down comes with a lot of risks; a lot of the time feed, and water may fall back out of the esophagus, after which the birds may inhale. Apple cider vinegar has no effects on a blockage, and squirting it into a bird this young could easily prove fatal - they have a limited sense of knowing how to properly swallow feed and water so easily inhale matter.
If the bird is still drinking water by itself, I would try adding an electrolyte, or poultry vitamin such as Sav-a-chick, or Nutri-dench to keep her hydration, and nutritional levels up. Any foods offered should be mashed Finley, and moistened down for easier eating. Hopefully, you can get your hands on something you can dislodge the feed with. Small fine, aquarium tubing, with the tip melted down, may work.
If the bird is still drinking water by itself, I would try adding an electrolyte, or poultry vitamin such as Sav-a-chick, or Nutri-dench to keep her hydration, and nutritional levels up. Any foods offered should be mashed Finley, and moistened down for easier eating. Hopefully, you can get your hands on something you can dislodge the feed with. Small fine, aquarium tubing, with the tip melted down, may work.