Here's a video of the "crow":
If she is really flighty, you may need to try to wait until she roosts at night to examine her (easier to catch) and possibly less stressful.
Since it's been progressing over a long period of time, look in her throat for any worms, redness, swelling, sores, etc.
Wondering if it could possibly be gape worms? Can you take a fecal sample to the vet to have them check for worms?