My 10 gals have been free-ranging all day for about a year and a half. They all put themselves to bed at night, no problem. They also all know their names and will come back from quite a distance if I call them. I also started with a covered dog kennel/playpen and brought them out in the morning and in at night to get them used to the grass etc for quite some time before moving them to a coop/run (also due to the fact that the coop took a while for the hubs to finish). As I carried them in/out I would talk to them and call them by their name. Maybe that helped them learn. I only let them out alone when they were at least 4 months old.
We had one Cooper's hawk issue last fall, but luckily he went after a saavy gal that got mostly hidden under a lean-to. She got pecked pretty bad in the head and I was worried about her eye, but she made a full recovery. The hawk has not been back, but I kept the gals all cooped up for a week or two afterwards. We have three dogs that help patrol the yard, and they had been on vacation with us when the hawk began lurking....but my gals are crazy foragers and are often in the woods behind our yard and all the way up the street visiting our neighbors; so they are on their own a lot. After our hawk incident I got a couple of fake owls (probably useless) and some metallic pinwheels from the dollar store. I put the pinwheels on the edges of the coop and at different angles pointed toward the sky where they catch the sunlight in different parts of the yard. I have heard that the flashing metallic disrupts the hawk's vision and/or reminds them of fire. Don't know if that's true, but it was cheap and easy to try (and the kids love it). FYI Sharp-shinned hawks and Cooper's hawks are fairly small (bird hunters/accipiters) and will swoop down from a low perch or even over a fence and kill a full-sized hen right there on the ground. We live on acerage and have many other hawks around but haven't had any trouble at all with the many red-tail hawks or the breeding pair of red-shouldered hawks that nest in our tree and patrol our yard (both buteos and more naturally prone to eating rodents and even snakes). Naturally. now that I have jinxed myself I am sure that one of my residents will get hungry enough to try the free chicken buffet in our yard. Late in the fall you get migrant hawks and 1st years that are hungry and looking for territory...and free lunch.
We absolutely love having the hens running all over the yard and "helping" us with our chores. 10 is quite a lot to have underfoot, but I would not trade it. As a bonus all 10 (3 different ages) went straight to the nest box to lay their first eggs. I was afraid we'd end up with a daily egg hunt, but that has not been the case. We don't have a roo (had to get rid of ours that turned out to be quite aggressive), but they can help keep free-rangers safe as well. Good luck and have fun!