Welcome.Hello! Just another thing to enjoy/have self sufficient and maybe share some eggs or take a few to the farmers market on occasion. However, just having enough for us would be sufficient.
I would like to have about 8-10 chickens to start with to see how it goes. And then if they can sustain themselves great! Maybe see if some of the hens will hatch their own in the future to keep replenishing young ones in. That would be ideal.
You will have to provide some feed and a calcium source.
As far as free ranging, I'd expect it to work out for a while. You should have a secure run to fall back on, when predators show up. I have to lock mine up every now and again, for a couple of weeks, until predators move on.