Quail should really never be mixed with chickens. They both carry things they can pass to each other even though you don't see any symptoms. They say at least 30 feet apart.
Get them on an antibiotic, preferably one of the Tetracyclines like Duramycin or Doxycycline. I had a similar issue in my Quail aviaries, this will save their lives.
This was one of the things that fascinated me about my Bobwhites, they were a bit wild. Far from tame, I kept them in large aviaries and they went about their lives as if they lived in the wild. Their little micro world they lived like they were free. Fascinating to watch!