Over the yeas I have used a number of Coys on the market today. As stated above sometimes they work and sometimes they don't. But I have found that the BuckWing Bobblin head is the best of the best.
What I have noticed is these coy's need some modification. and I have changed them a little, adding a little more darker color up the back of the head and have also cut out more room at the bottom , so the spring can move freely back and forth to make the coy look as if it is feeding. Also I have glued the nut on the top and did not tigthen it down so the decoy can easyly move around the bolt it is sitting on. I also cut some of the material away from the sides of the head that moves back and forth to allow the head to bobble more freely.
Now here is a little tip I use quite often. If you place a decoy out and work a bird or birds into seeing range and the birds will not come into your shot range , but instead move off and work back " As to get the hen to come to them" when the bird moves off , get up fast and get out and pull the decoy and then quickly move back to your setup point and sit quiet and don't call
Gobblers hate that and will walk into where the decoy was to see where the hen went. Try that on the next frustrating hunt with decoys...BT