Personally I would set up both options. There are times when the 3 acre paddock won't be a good idea.
In a perfect set up for chickens, the owner has a couple of options. In my set up, I have a run large enough to keep them confined comfortably. They can and sometimes do stay in the run/coop combination for days at a time. The birds have free choice to be in the run or the coop 24/7. I don't ever lock them in the coop at night. This way, they put themselves to bed, and get out and about when they wake up. This allows me to be gone for a couple of days. It is also a retreat when I get a predator hanging around for a quick and easy meal. This set up is pretty darn secure, and I have proofed it through trial and error.
But I do like to let mine out and about. The more consistent you are about letting them out, the farther they will roam. Sometimes, they will hid a nest out in the wild, but generally you can just retrain them by confining them to the coop/run for a few days.
Mine have always come back to the coop by themselves to roost up. I do have to go down and shut up the run, if I have let them out to free range to keep the night time predators out.
The problem with the 3 acres is that you more than likely will get predators, once they find you, you need a safe place for the birds you have left. I don't let my birds free range on windy days or overcast days, it gives the advantage to the predators. Also, I don't let my birds out to free range on a consistent schedule, say every morning at 8. Somedays they are out all day, some in the morning, some not till afternoon. I have a rooster, which helps, but is not fool proof. If you free range, you need to realize that you are pretty likely to loose some birds, and dang nab it, it generally is the one you like best!
Edited by Mrs. K - 1/10/16 at 9:23am