if you have a specific question of someone, it is best to PM them. It's just luck I saw this. Also, there are a lot of other people on here that can answer your questions, many better than me. Try to figure out a thread title that describes your question a bit so the right people are likely to look at it and just make your best guess as to which section to put it in. Please take this as helpful suggestions. I'm not criticizing or anything like that.
I use the 4' high netting. Young chicks can go through the openings so your chicks need to be big enough they cannot squeeze through. That makes it a bit rough with a broody with young chicks.
Chickens can easily fly over this 4' high netting. That's hardly ever a problem for me. I've never had an adult fly out of the area. One time a grown hen slipped out through the coop door. While I was trying to herd her back to the coop door to get her back inside, she just flew over the netting to get back in with her friends. She easily cleared that netting by a foot. Yet they never fly out.
When I have juveniles, occasionally some will fly out when the older chickens start harrassing them and trap them in a corner. This is usually around the age if 8 to 12 weeks. I don't usually integrate them earlier than that unless they are with a broody and by 12 weeks they are usually settled down enough that it is not a problem. When they get out, mine go to the grow-out coop area at night where i can catch them and put them back in. I have not lost one that's done that yet, but yeah, they are at risk.
Some people have reported they can keep them contained in a 3' high fence. I have had some excape over a 5' high fence. It just gets down to motivation. If they want to bad enough, they can get out. It might be them trying to get away from a pecking order fight, a hen trying to avoid an amorous rooster, an integration thing, or sometimes a hen develops a wanderlust and just likes to roam. I had that happen once in my run with 5' high fencing. A hen learned to get out. I think she first did it to avoid a rooster, but she learned she could. Then she taught two of her buddies to go with her. I raised the fence on the run to about 8' to stop that.