In my opinion It all depends,if your hunting in woods or somewhere with cover,then no decoys at all.Bring the turks in just by calling and once theyve locked on and u here them gettn closer stop calling it will keep them coming searching for the hen.
If ur tryn to get birds to come across a field,Then yes use decoys. A hen with a jake works ok.Cause it brings in big toms and not so dominant birds.The SMALLER males wont be intimidated(scared of a fight) sort a speak.
But with using decoys,theres always that chance the gobbler ur hunting will hang up!Meaning wont come in any closer.Cause in nature the hens go to the gobbler!not vice versa.Try with and if a specific bird is hanging up when he sees the decoy try without.
Good luck..