How old are they? My 19 week old's get scared of the sound of a car coming by, if they're in the front/side yard they scoot away from the road. I was wondering if yours are maybe too young to hear cars coming? Or just don't care?
Haha I have so been there with herding chickens, like sand that's a new one! XD
What works best, seriously you'll be amazed, is leading them with chicken scratch. I bought 5-grain scratch and added some sunflower kernels. My girls go CRAZY for it! I throw very small handfulls and back away slowly and they just swarm me. I don't really drop that much, it's just seeing it fall that excites them (like a cat!)
I've herded soo much more successfully this way than trying to move them with my body. I think I need some kind of sheepdog to make that happen
Also what Guppy said is spot on, they want to be under something - low tree, low bush, etc. If your pasture is wide open, they see that as dangerous because they (rightfully) fear predators from above - hawks, owls, etc. You could give them objects to hide under to encourage them hanging out in that area.
And! Just be patient.

My girls spent seriously 3 weeks under 1 bush, when I have acres and acres of space. Then, they slowly started branching out to other bushes, running across the open yard to the opposite tree, and venturing into my front yard garden area. They really love bushy/overgrown areas! If your road is like that, or maybe the neighbor's yard is like that, it could be what's drawing them there. Best of luck!