Smaller doesnt always mean quieter tho. I was surprised when I went to the county fair, those lil roos and some of the hens even made SO much noise for lil boogers!
biretta, I forgot to say that altho I live on a very busy street, my situation is much like yours, I used to let mine out all the time when I was outside, then started putting them in the pen when I finally got it finished, they were quite big when that happened. lol
Even tho my noisy girl is fairly quiet, I DO let them out about an hour to 1/2 hour in the eve every night before their bedtime, and now my silly red x link stand there and ruuuuuaakkkks until I let her out. She probably begins at about 5:30, she is out there trying to get me out right now. If we were in a REAL quiet neighborhood, I might notice it more, but it sure wouldnt be noticeable to the neighbors. And yes, I DO think they learn from each other, what gets you out there.
If they have distractions, it helps a lot, let me tell you. Any way you can build them a tractor, to put it on fresh grass every other day or so, shouldnt hurt the grass if you move it every day, and it keeps them occupied. Sometimes hanging an apple, or cabbage or somethin for them to peck at, also occupies them. They really do get bored, especially if they are some of the smarter ones. I think boredom is one of the reasons they want out so bad.