In a small bowl combine the juice from 3 of the lemons, chopped sage, garlic cloves, red pepper flakes and 1/4 cup olive oil. Whisk to combine.
Run the frozen Tyson® Frozen Boneless Skinless Chicken Thighs under cool water to remove the layer of ice. Place the chicken thighs in a zipper bag and pour in the marinade. Refrigerate overnight.
Preheat the grill and brush the grates with oil.
Remove the chicken from the marinade and sprinkle with salt then place on the grill.
Grill the chicken for 3 minutes and then rotate the chicken 90 degrees to get a nice cross grill marks. Grill the chicken for another 3 minutes. Turn the chicken over and grill for another 5 minutes. Check for doneness.
Serve with the extra lemon.