I am sorry this is happening...I think you are doing what you can and only other suggestion is to sniff check the food closely because I though crop impaction can definitely happen moldy or musty food can cause catastrophic illness also. If their crops remain hard after no food for multiple hours though I would stick with the impacted crop theory.
pretty much all of them had emptied crops now. Just put in some very watered down chick crumbles so I could watch them all run around. Everyone looks okay but today is my only day off for next two weeks so I'll be watching like a hawk. I do have one turkey that looks like it has a weak left side. Up walking and eating but seems lopsided with wing extended a bit. Not sure if I should be worried about it.