If you have to chase them to catch them, you may just make them more afraid of you.
I managed to terrify mine today by accident so it may take a bit to rebuild their trust in me! I had some elderberries in a fairly large box and decided (like a fool!) to toss them over the fence to them instead of opening the gate to their run. They were all standing there looking expectantly at me, as I had given the "treat" call. But as I lifted the box over my head, George screamed in panic and they all ran away in terror! I have never seen anything disappear so quickly! They were there, then they weren't! And they would not come back out, no matter how i coaxed and called. An hour later when I came to give them a little scratch and let them out to free-range, none of them wanted anything to do with me. After all, from their perspective, my head had suddenly become a big, brown rectangle spewing black blobs at them (that later proved to be delicious berries, but that's beside the point!).
Ah, chickens!