They stay close, at first, then over a period of time they range farther. A lot depends on the breed and the terrain. Regular barnyard breeds never go very far.......Pop
My backyard is 16k square feet & my flock free range all over it. When one of our hens starts making her "gotta lay an egg right now" cluck, our rooster will escort her and the others to the coop. When I look out the window and see a line of chickens walking to the coop, I know it's egg laying time! When the daylight turns to dusk our rooster will start to lead everyone closer to the coop and just before it gets fully dark, he'll be the last one to enter for the night, making sure his ladies are all safe inside.
I have multiple free range flocks. Some are dominiques and some are American game. My dominique flocks are started as releases of chicks (n= 9 to 36) from mobile coops / chicken tractors when chicks are about 8 weeks post-hatch. They initially stay close (almost within shadow of coop as Pop and others indicate but over next few days they quickly range up to 400 feet away. Ranges I see are seldom circular, rather they form an oblong shape which encompasses roost / coop, water source, quality foraging area(s), feed source if provided, and at least one day roost where they can avoid elements especially during middle of day. If resources farther apart they will compensate within limits. If distances between resources to great, then that is when they shift roost sites. Game flocks very similar although they will readily use larger home ranges. Some are even prone to fly from resource to resource to avoid walking through high grass or out in open too far. Game flocks approximate better foraging breeds. When flocks are of mixed content, then movement range is more a function of breed with greater ranging tendencies. Some breeds range poorly, especially the production meat breeds. Breeding status of hens if flock small can also influence ranging as I am observing with front porch flock that I monitor closely.
I have RIR's & live on a hundred acres. The land is used for growing hay so its mainly cleared. I have two barns. One of the barns is where I live. There's trees around the barns. The chickens feel safe under the trees. They never go beyond the trees. They don't use a quarter of an acre. That's two flocks of a total of 27 chickens.
