In that situation you are describing with multiple hens. Just soft clucks, purrs and scratching the leaves. No yelp calls! You want to just sound like a feeding group of contented hens. That sometimes entices the hens to come crash the party.
When he was following a single hen, however it's super tough. If she is almost ready to breed, she won't want to be near other hens. And if she is almost ready, he won't want to leave her. You did as good as you can do in that situation just to get them in range.
Best bet is to get permission to hunt the powerline. Sometimes they aren't going to leave an open area to come back in the woods to anything we do.