I grew up out in the country. When we got chicks from the pet store (or hatched our own) they stayed in a small separate pen (an old rabbit hutch sometimes) with a heat lamp until they were big enough to go out in the chicken pen. We always had several chickens at a time. So we had a large coop with an open style pen connected so they would have shelter and a place to lay eggs, as well as a large area to roam around safely outside. Sometimes we'd even open the pen and let them just roam free. They always went back to the coop at night to roost, then we'd close the door until we wanted them out again.

I actually miss having chickens like that. Of course, I am the baby, so I never had the responsibility of taking care of them like my siblings did. I did go out and gather eggs though.
And I'd help feed them too.

But yes, you'd need an enclosed structure with chicken wire to keep them safe from predators......and George. I'm sure you could buy a structure if necessary too.