I have 2 1/2 week old Coturnix's. Hatched them here. I changed their water one morning and when I came back in the room I had one with its head thrown back and flapping it's wing. I grabbed it and starting rubbing it's crop (I had no idea what to do) it threw up water and like snot?? As I was rubbing that one I had 11 out of 21 start the same thing. I got them all to "threw up" the water and saved all but one. They were fine after that. Tonight I had 6-7 start doing it again and lost 3. They have been fine for about 4-5 days. Why are they doing this? There is no mildew in water or food and the are inside with no other birds. I am new to raising quail.