Flushing the crop seems to have worked well for you. I've also had good results recently with the following:
Bring the bird inside and confine with a tank of ACV water (1 tbsp in 1 gallon of water)
Induce vomit by holding bird head-down (hold in arms, bend at your waist until bird's head is down, massage crop and allow contents to empty for a moment, then upright to rest/breath, forward again.) My bird was vomiting on her own anytime she leaned over, she was so full!
Withhold food for 24 hours, but not water.
Ask vet or pediatrician/physician to prescribe infant Nystatin oral drops at your local Pharmacy. THis is a medication that kills yeast in the digestive tract but does not penetrate the stomach lining. (Typically used for thrush infections in babies.) It will not go into your bird's blood stream to get in eggs, but will destroy the yeast build-up in the crop. Cost is about $17. Also pick up some OTC baby mylicon drops (for gas.) Give your bird a tiny bit of bread saturated with 1 drop of Nystatin 4x a day for 4 days. And a bit of bread with 1 drop of mylicon 2-3x a day for 1-2 days as needed. (I do bread to be certain the bird eats the full dose and it doesn't get wasted in a food mix.) The Nystatin will begin to work in about 48 hours, the mylicon will reduce the gassy gurgling pretty quickly. During the first 48 hours feed the bird only small amounts of soft unsweetened food, and preferrably things that aren't made with grain except the little pieces of bread with meds. (I like plain yogurt, scrambled egg, baby food meat/pumpkin/peas/spinach.)
After the first 48 hours, you should begin to see some large, mucous-y poops as the contents of the sloppy crop begin passing. As the crop deflates, you can try adding cooked/soft oatmeal or soaked crumbles to your food mix. See how it goes. Continue the Mystatin drops on bread for the full 4 days, and up to 5 to be certain all yeast is killed with no lingering pockets.
This regime worked beautifully on my bird, who had a crop the size of a softball! She is back to her old self in 48 hours.