Those are hens that have either done been bred, not going to breed, or are nesting (or thats what I think anyways lol). I'm having the same luck as you. Can call every hen in the county in just not the ones with the gobblers. Its been either feast or famine here and I havent been feasting
Cant find a lonely tom. Can get the hens to answer and to even come in some what but not in shooting distance. Fooled with 2 gobblers wednesday morning and I finally seen them about 100 yards in the holler below me they had 8 hens! The hens chatted with me for a bit but eventually flew across a river taking them away
Another week or so it should turn around.