Decoys aren't necessary under any circumstances in my opinion. Sure field birds can be tough, but instead of making it a shooting match make it a hunt and face the challenge with no decoys.

Without decoys our harvest might be half of what it is now. The biggest issues I have with them are they allow the super dominant birds to be taken leaving hens that may go unfertilized because the other gobblers are beaten into submission by the time the season opens. They also allow hunters who have no chance of being successful to have a very easy avenue to harvest birds.

Set up smart, hunt smart, and learn how the birds use the land you're hunting. That's the recipe for killing lots of turkeys without a Chinese imitation.