To make the marinade: Whisk the egg, then add the oil and whisk it together until it's all mixed. Shane says this is the beginning of a remoulade. Then whisk in your dry ingredients (salt, poultry seasoning and pepper) along with the apple cider vinegar.
If you like, reserve a little bit of the marinade in a small cup and refrigerate to use as a dip later.
Pour the marinade into a gallon-size Ziplog bag and add chicken. Seal the bag and make sure the chicken is fully covered with the marinade. Shane says to marinate it for up to 24 hours, minimum of 8 hours.
Be sure to toss out the used marinade that the chicken was marinating in (have to say it, just in case you're tempted).
Preheat your barbecue grill. You can optionally oil the grill but there's so much oil in the marinade that it should be OK without it. Grill the marinated chicken over indirect heat on the grill (to the side of the grill), flipping it halfway, until it is almost fully cooked at 165 degrees (use a meat thermometer), then finish it off over the flames until it's fully cooked.
For leftovers: slice thinly and put into quesadillas or on top of salads.