Sounds like stridor, which is caused by a partial obstruction in the airway. It can be from a bit of feed or something stuck in there and may resolve on it's own. If it keeps up I would check inside her beak and throat as far as you can see to make sure there is nothing obvious lodged there. It can also happen if a bird has a respiratory infection, so look for any discharge from the beak or nares or eyes. I have had a couple of hens do this when overheated also. She sounds like she is either coughing or sneezing occasionally, so could be just trying to clear the airway, or could be another indication of respiratory infection.