where are you from?? could just be they arent "hot" yet.....seems that only "hot" birds will shock gobble......and the ones that sound off easily during the day are usually your best bet to hunt...atleast thats what i found for MY area......your area may be diffrent....but around here if you dont get them to come off the roost that means you spooked them or they had hens....then its time to sit and wait for them to come back without hens later or run and gun and shock one to give up his location....sometimes they will shock once.....but i like to get them to gobble a couple time...to make sure they are hot birds.....and to figure out what way hes heading so i can get infront of him..i could go out right now and blow a crow call all day and i doubt i get one to respond...they just arent too hot yet up here....its 25 degrees!..sure i bet they gobble a little bit already but the action still isnt near peaking yet....but im going to scout/fish......all i ever use is a crow call....but ive heard them gobble to geese.....owls...coyotes...peacock calls(actually works well) and even a spring thunder storm had birds going NUTS one day....that was probably the best.....thunder.....it was 3 or 4 in the after noon and they were going NUTS every time it thundered that day...good luck