Quail dying

I have Tuxedo quail that are becoming sick and dying. I had 3 of them. About a week ago one became sick. He started losing his balance and then his head tolted to one side and he couldnt get his balance. He didnt seem to have any breathing problems, wheezing, runny nose or anything. No dirreha noticed. He died in about 5 days. The remaining 2 seemed fine. Then about 2 hours ago I noticed one of them seemed to be having problems with cordination again. He will try to get and walk but just fall over and cant get up it seems to be getting worse. His eyes seem clear and once again no breathing problems or runny nose. He doesnt have the head tilt or anything like that actually he moves head around well and seems clear there. These are pets and live indoors so havent been exposed to any outdoor things. They are in a wire bottom cage so they arent in their droppings. The water and food are changed daily. I have removed the sick one and isolated him and then took the remaining quail out, who seems ok, and scrubbed the cage and bowls and all. They were by some older Bobwhites, they are about 17 weeks old, but they all seem ok but I did scrubb their cage also and moved them away from the tuxes. I have read up on common poultry diseases but nothing seemed to match his symtoms. Anybody have ideas or thoughts? My main concern is preventing the spread of anything. I have exotic birds also but they are in a different room but I dont want anything spreading to them or anything that can be contagious to humans I have 3 small children that like to play with the quail. Thanks for any info.

Christie