I did quail on the ground outside for a couple years. I started with 21 total. 3 male, 18 female. No fighting. But I had a lot of space. The aviary is about 6 foot by 9 foot. My numbers went up and down over time due to hatching and selling chicks.
Here is my link to my build and adventure:
https://www.backyardchickens.com/threads/paneuberts-quail-aviary-adventure.1094484/
Trying to reply to some of the other comments have seen in this thread so far.
Quail will sometimes use ramps. Here is a photo user "coturnix condos" posted in my build thread.
They have/had a little coop and then a larger run down the ramp.
I had some quail lay eggs together in clutches, while some did not. I did have a couple at least appear to go broody, which is also not common. I know I at least had a couple spots in the aviary that were preferred for egg laying locations. Not nests like chickens, but still I could expect to find eggs in certain spots.
They can flush up and hit their heads. You pretty much either have to have a low ceiling so they cant get enough speed to hurt themselves (which is why people can raise them in small cages with less than a foot ceiling height), or a high ceiling so that they lose speed before they hit (so like mine where it is more than 6 or 7 feet high). Hope that makes sense. That being said, mine did not flush very often and I bet yours will be fine. Even if I was chasing them trying to catch them, they mostly ran, or jumped. Now that was coturnix. When I raised a batch of bobwhites.......I had them above my ceiling panels.....they would pretty much run up the sides of the aviary and get in the ceiling. They can definitely fly. Those were very young birds as well. Same happened with California Valley Quail. Basically any really wild or native quail will be a good flyer, while coturnix are just little fat birds who can't do much.