I use these
https://www.amazon.com/gp/product/B08YP4S5KX
This one needs a companion or three. Quail are social and aren't meant to be alone. At this young, the temperature in the warm end of the brooder should be in the mid 90s.
Edit: Before you get more, if this one is a bobwhite, make...
And just what did you expect when you got these animals that you know nothing about? You are unwilling to answer basic questions to help with their care and are unwilling to get necessary equipment for their needs. Did you expect them to thrive on hopes and magic?
You have consistently not answered questions so we can help you. Please post a picture of your setup so we can see what's going on. What is the temperature at the warm end and the cool end of the brooder?
1, 2, 3 are male
4, 5, 6 are female
7 is male
8, 9, 11 are not feather sexable
10 has clear crescents on the face and some spots on the chest, so I'm leaning towards female, but am not 100% sure.
You could try adding a shot glass filled with water to the incubator. That adds some humidity but has a small enough surface area that it doesn't add much.
30-35% is probably about ideal. I've found that up here at higher elevations lower humidity during incubation is better, but higher at lockdown (up to 65-70%).
When I lived in P-town my ideal was around 30% humidity during incubation and up to 50-60% was best at lockdown.
It's possible that they're siblings, but as long as there are no genetic defects hiding in there, they will still be fine for a few generations, at least. It won't hurt to add some new genes, though.