chaz

I'm not sure if best but this worked for me. I was able to defrost a 56 lb frozen but dressed pig in a large igloo cooler within 4 days. I placed two 10 lb bags in the cooler with a plastic table cloth above the ice so the pig was never in water. The pig goes into the cooler on its back with legs up. I placed a 10 lb bag of ice on top of the remainder of the plastic table cloth that was draped loosely above the pig.
I used some cardboard to fill the empty space at the end of the cooler. There was sill plenty of air around the pig for the temperature to remain constant all around. By using a wireless thermometer I was able to be sure the cooler stayed cold enough. With this technique the cooler stayed between 33 and 36 degrees. Temperatures for thawing meat should not exceed 40 degrees f. I checked it each evening and morning and replaced ice as needed (two more 10 lb bags). I started the pig on a Tues afternoon. By Friday evening the pig was mostly thawed and easy to insert a needle with marinade into the hams.

Tip: Though I ordered a fresh not frozen hog it came in frozen. By calling to check on the order you can pick it up early enough to thaw if the same thing happens to you.