Hi scorwin,
louclare has the 'secret'. Once your chickens know that you are the source of all the treats, they will come running to meet you. Some folks here use a special call or noise, such as 'here chickens' or shaking some pellets or scratch in a can so the chickens get used to the sound and come running.
When you first get them....don't let them free range. They need to spend a couple of nights in the coop so they know where to go once darkness is approaching. When they associate your coop with their nightly roosting spot, they will go in on their own accord. Hopefully you have a run of some sort or a large enough coop that they can spend a day or two 'confined'.
Right at the beginning, some folks also use a flashlight or light in the coop to guide the chickens to home-to-roost.
Get them used to coming to you and even if they are scattered around the yard....when your call or sound that is associated with treats is heard, they will scurry to get their handouts.