I think my chickens know mommy equals food. Mommy also equals safety, and more food. Mommy also can warm feet on a cold day, oh, and also brings food.
My chickens come running whenever I'm outside. If I don't have food, most of them wander away, but stay within the area where I am. When hubby and I are out in the yard working, usually we have about a dozen chickens close by. They know there's no food, but either they have eternal hope or they know our presence will keep them safe. If we are outside with anything in our hands, we are immediately surrounded and can only shuffle forward an inch or two at a time until they all realize we aren't carrying food.