^15.5 lb turkey, extra large turkey fryer. How much oil? Turkey
  already seasoned. What we did: Put Turkey in two garbage bags.
  Put turkey in fryer. Used 1 gallon milk jug, filled with water.
  1, 2, 3 gallons. 4th gallon was too high. Took a few cups out.
  PERFECT. And that's how much oil we used to fry the turkey.^