I don't have to call mine at all. I think they know the sound of my truck. They all pile up near the corner of the run. I can hear them acting all crazy behind the house and I park in the front. On my day off I can walk out and not hear anything. When they get out and free range on their own, I yell "What are yall doing out here? Get back in your run!" And they run to get inside. LOL!
When I can't see anybody I will yell " WHERE'S MY CHICKENS" and the come running/flying across the back yard to me. I follow it up with " CHICKCHICKCHICKKKKKKKKCHICKCHICK"
By the time I finish they practically standing in my shoes begging for goodies (and I use to think dogs were the biggest beggers in the world).
I say "hello my girls", although with my accent it comes out more like "ellurh muh gurh-lls"
Edit: forgot to add that if they see me come with my fist clenched around something then they come running because they assume it's grain, and the same if they see my with a ready meal container, because they assume it's porridge - their favourite.