chickens are creatures of habit. they know where home is. Generally, they do not stray far from that. If you are worried about it, start training them! start offering them treats in the coop, and find out which ones make them go nuts! start carrying that special treat with you, and giving it to them when you go see them. Once they are conditioned to come to you, try it with the run open. Hang out with them for a while, then go into the run, call them, treat them, and close the door. Slowly extend the period of free range time until you are comfortable with letting them go unsupervised. Most flocks will put themselves to bed when it starts getting dark. Then, you just close the door and secure them (how long have they been roosting in that coop? I keep mine in a new coop with no free range time for a minimum of three weeks to train them where home is).
One thing I would make sure of though, is that your neighbors are okay with it. when they get more freedom to free range, they may wander onto your neighbor's yard. Chickens are cheeky, and have NO respect for property lines! I think I read somewhere that chickens generally stay within 100 feet of their coop or something like that?
Granted, I have a half acre, but my chickens rarely leave my yard. Sometimes, they go chill on the porch rails at my neighbor's place (he has a cat feeder), but they always come home at night (I say "they", but in reality, I only have one at the moment. Free ranging has the possibility of opening your flock up to predators. It's something to be aware of).
Oh, last thing. Not to feed your chicken addiction, or be an enabler or anything, but for the sake of that pullet, you are going to need at LEAST one more...once she reaches sexual maturity, that rooster will be relentless if you plan on keeping him, and if you don't plan on keeping him, she will need another girl to keep her company. She needs more players on her team for support
