I don't let mine free-range full time because they are a bit too friendly. They come into the house and hang around on the patio which can be a bit messy. The dogs thinks she is a chook so she digs into their pen and shares their food and then they go out through her tunnel and free range for a few hours until I move their coop again. The theory is that they are allowed to free range for a while each day and whenever the grass under their coop is scratched out the coop is moved. Thanks to the dog's efforts the coop is moved a bit most days.
They're very keen on mulch so I spend lots of time putting my mulch back where it belongs. Chickens and perfectly manicured gardnens don't really mix so if you want them to free range you will need to set part of your garden aside that you're ok with having some mess and poo.

