Another grinding achievement. For me, turkeys didn't start appearing until I got to Mexico, and then after that they would randomly appear elsewhere as well. Unfortunately they are pretty rare, so getting 100 will take a while.
One strategy is to hunt on a Sunday morning in Russia on Rookie using the Compound Bow or Bolt Action. I ran into 3 turkeys almost every hunt, which means it will take a little more than 33 hunts to reach 100. Also, when hunting turkeys, make sure to bring a bow or blowgun so that if there is more than one on screen, they don't run away. If you are good, you can use the Bolt Action and take down all 3 before they flee. The achievement popped up right as I killed my 100th turkey, I did not need to complete my hunt.