Special equipment: turkey brine injector, vacuum sealer and bag and sous vide immersion circulator
For the brine: In a large stockpot over high heat, combine, the apple cider, 4 cups water, kosher salt, maple syrup and black peppercorns. Bring to a boil and then reduce the heat and simmer for 5 minutes. Turn off the heat, add all but 2 sprigs of the thyme, and let the mixture cool. Refrigerate the brine until thoroughly chilled.
For the turkey: When the brine has chilled, fill a turkey brine injector with liquid. Insert the injector into the turkey breasts and drumsticks, filling each with brine. Transfer the turkey pieces to a vacuum seal bag and seal according to manufacturer's instructions. Refrigerate for 24 hours.
Cut the bone out from the thighs, keeping the skin intact. Reserve the bones for stock. Sprinkle the inside of the thighs with salt and pepper. Place the thighs, skin-side down, into a vacuum-sealable bag, making sure they lie flat. Add the sage, the remaining thyme and garlic to the bag. Using a tablespoon, place the duck fat around the thighs. Using a vacuum sealer, vacuum and seal the bag according to the manufacturer's instructions; be sure you have a smooth, airtight seal. Place the bags on a sheet tray and cover them with a second tray. Place something heavy on top of the sheet tray to press the thighs down. Place the tray in the refrigerator to press overnight along with the turkey breasts and drumsticks that are brining.
Prepare a sous vide immersion circulator for use according to the manufacturer's instructions. Preheat the water to 150 degrees F. Remove the sealed bags from the refrigerator. Carefully place the bags containing the pressed thighs into the circulating water and cook for 2 1/2 hours. During the first 30 minutes of cooking the thighs, remove the breasts and drumsticks from the bags and pat dry. Add the salt, pepper and maple flakes to a coffee or spice grinder. Pulse until ground and completely mixed together. Pour the mixture into a large bowl. Place the turkey breasts and drumsticks into the mixture and toss to coat. Place each half breast and drumstick into separate vacuum-sealable bags. Using a vacuum sealer, vacuum and seal the bags as instructed above. Place the bags into the circulating water and cook for 2 hours. (The thighs, breasts and drumsticks should be done at the same time.) Remove from the water.
Just before serving, preheat oil in a deep fryer or large, heavy-bottomed pot to 375 degrees F. Remove all of the turkey pieces from the bags and pat dry. Working in batches, fry the breasts and drumsticks until golden and crispy, about 5 minutes per piece. Transfer to a carving board.
In a large, nonstick saute pan over medium heat, warm 1 tablespoon of oil. Place the thighs, skin-side down, in the pan and cook until golden and crispy, about 12 minutes. Turn the thighs over and cook until warmed through, 2 to 3 minutes more. Slice the breasts and thighs and arrange on a platter with the drumsticks.