How about bribing them with food. Chickens go crazy for cracked corn, or even bird seed. Maybe open up your chicken run, and sprinkle the food around, calling them as you do it, so they see it.
If they're super shy, and the food doesn't work, another way would be a net, like a fishing net with a long handle, or, as a last resort, keep an eye on them, and when it gets dark, you can simply pick them up. They get really docile at night.