Got busy and didn't see the post on the brooder temp but Nabiki is right....90 to 86°F is too cool for newly hatched chicks.Your brooder is cold for new hatched chicks. I usually start mine in the high 90s, close to incubator temperatures. Chicks can't regulate their body temperature, so if they're getting down to 86 in the warm end, that could be enough for them to die.
Can you provide a bit more information on the game bird food that you're giving them? I've seen some "quail food" with as low as 12% protein. Chicks should be getting something around 28% protein.
The adults should be getting a feed with around 20% protein.
For the 1st week, I have my brooders at 95 to 98°F on the warm end and around 85°F on the cool end.
Also, I place the feed and waterer's in the cool end.