You need a vet if you're really trying to save your birds. It's too late in the game for someone to say it could be this or it could be that. If you're losing birds it will continue. I would be most inclined to think it is enteritis. If a vet is out of the option, you should dissect one of the dead birds and see if you can see any obvious maladies present, like blood or ulcers in the intestines. Enteritis often causes 100% mortality if not deal with in the first few days. There are several medicines for treatment of enteritis, so if you can purchase one over the counter you have nothing to lose in trying it.Baby quails have been separated from flock as they get pecked so that's good.
However my last male isn't looking flash so have just moved him into ilsolation and **** he has diarrhea too.
also found this... I keep my quail on the ground with lots of room and natural habitat.
Quail Disease: This is a bacterial disease. There are two forms of quail disease. The first form is highly chronic and a mortality rate of 100% is observed among the infected birds. The major symptom is diarrhea, with white colored feces. The second form of quail disease prevails for a longer period of time. Loss of appetite is the major symptom. Birds affected with this disease will die within 6 to 10 months due to gradual weight loss. Medicines like Streptomycin and Bacitracin are administered in the treatment of quail disease.