I learned a boatload about calling gobblers by feeding a flock thru the winter seasons. Didn't take but a couple days of throwing sweet chop horse treats to a flock before they decided I wasn't any danger and they would let down their guard. I'd sit on a bench in the backyard with a coffee can of treats and toss a handful at a time.
The hens come closest, but gobblers would mix in, too. There are dozens of small little noises they make while feeding, conforting happy little sounds that relaxes the alert birds and says all is well. I can't make most of those sounds on a box call, wingbone call, slate, or diaphragm...BUT I can do with with my voice.
Best of all, since those calls are so low and quiet that you don't need to really throw them hard and fast. Just whine, wheedle, twitter, pop, and click in whisper tones. When a gobbler is 50-60 yds away he can hear these just fine. It says to him that the hot chick is into a nice patch of fresh greens, crunchy bugs, and gushy grubs. It says she is fattening up and is happy as a coon in a corn crib. And he knows she wouldn't be chit-chatting like this if there were any danger in the area. Haven't we all wanted to convince that suspicious tom that all is well?
Oh man, I love talking turkey with the turkeys. Spend that time talking back and forth with the hens, learning their rhythms and intonation. You never know when that last little bit of dirty pillow talk will seal the deal!