Like Andy and catman said, they don't roost in trees after incubation. They roost in trees while they are nesting though, not starting incubation until their clutch of eggs is complete.
I think the poults can fly at 14 days. If you come across some and spook them, lots of times they will scatter like a covey of quail, except landing in trees instead of flying off and hitting the ground and running. Although I have seen quail lite in trees and have seen poults scatter fly and run.
They start whistling at each other shortly after they break up. Then hen starts yelping loudly and yelps a bunch to "assemble" her brood back together.
If the poults can just make it to where they fly, their odds of survival increase. Then I think at either 7 weeks or 10 weeks, they are full plumaged with no downy feathers. Making them less susceptible to hard rains.
If they can make it to the middle of August/September, they got a good chance to make it to be a breeding adult.
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