I just wanted to give an update. After our 4 hens got away, we got 3 pullets. I built another coop for them. 2 of the hens that had escaped would come to our yard during the day (maybe because they saw and heard the young hens), but would hop the fence as soon as they saw us.
On one rainy day about 1 week after the hens had escaped, we saw that those 2 hens were in the original coop that I had built for them. They were hiding from the rain, I'm assuming. So I ran out and closed the door on them. So now, we have 2/4 of the hens back in the coop! They've been in there since and have been doing well. But they still haven't warmed up to us. They will come out to the run, but they go back in the coop when they see us.
As far as the other 2 that got away...we still haven't had any luck getting them back. I climbed up a ladder to try to grab them one evening, but they flew away even higher.