I have 5 acres, mainly wooded. My birds free range within a 100 yard radius of their roosts. They could go further if they choose, but have not.
I have the following breeds:
Standards
Barred Rock, RIR, Easter-Eggers, Black SL, Gold SL, Dark Cornish, Buff Orp, Cubalaya
Bantam
OEG, Japanese, d'Uccle, Seabright, Cochin, Silkie, Brahma
The OEG are the more adventurous and tend to be the ones that go out the furthest. They end up leading the other birds out with them, otherwise they'd probably stick closer to the house.