So the first major note for the grilled chicken is I believe it's technically broiled not grilled. The folks who work the hot foods over in Brighton have the best fried chicken from a Star that you're bound to find anywhere. I've also eaten piles of this from everywhere so experienced at least. The notable thing for both is look at the tag that comes out, I don't have a grilled tag nearby but given they double dip their fried I'm going to guess they brine their grilled which also helps keep it moist over time. If you'd like I can snag one tomorrow but I think the big thing is that you'll want to brine your bird, let it dry out, and then stuff whatever seasoning you like under the skin and then cook it at 425. Keep an eye on color and while the skin might be a touch crispier than Star you're in the ball park. They also might use sugar which helps with balancing seasoning as well as browning. Let me know what questions you have and maybe I can get them answered.