This being our first year with chickens and ducks, we started letting them free range and found that the chickens pretty much stay within a couple hundred yards of the coop.
The Indian Runner ducks on the other hand are a different story. I have caught them in our neighbors back yard (they said they did not mind), in our front yard by the road, and pretty much just about everywhere on our 3.75 acres plus like I said our neighbors backyard.
Our biggest issue with the chickens free ranging is that they spread the mulch in our flower beds all over the place and have been known to eat the low hanging roses and some of my 5 year old daughters flowers too. Oh yeah almost forgot, they love to be in her sand box too. To combat these minor issues, we have only been letting them free range for a couple of hours at the end of the day after I get home so I can keep them out of those areas.