If not, she probably just has enough blockage to really irritate her. There is information on impacted and sour crop in the first link in my signature. You say her crop has been large for a long time, does she have access to grit?
If she appears to be yawning, though, I would say it is gapeworm, which I believe can be treated with a broad spectrum wormer. That first link in my signature also has information about treating worms. You may want to research gapeworm to see if that could be the issue.
If she appears to be yawning, though, I would say it is gapeworm, which I believe can be treated with a broad spectrum wormer. That first link in my signature also has information about treating worms. You may want to research gapeworm to see if that could be the issue.