What type of decoys are you speaking of? I would think that this is a deer forum you would be speaking of deer decoys, correct? And if so, yes, I have used deer decoys several time with various mixed results.
Very first time of using a deer decoy I used a ready alert doe decoy with FRESH doe in heat urine on a drag rag. Put out just before sunrise. Was in stand less than a hour when a 139" 10pt came across the fields chasing a real doe. Saw the deke, slammed on the brakes when he hit the drag line, came straight to the deke. Left the real thing for a fake. Cost him dearly.
Have taken several deer over the dekes. I call them jack and jane. I have a small basket rack 6 pt I use when the rut is on and on the ready/alert position decoy. I have used the other, a feeding position, and have come to find that without the antlers, EVERY doe that sees it, does nothing but blow, stomp and snort at it. I use them more as a buck than a doe. I have taken the legs off the ready deer and set it flat on the ground and put the antlers on the grazing deke facing it with great results!!! Had a REALLY nice 14ptr 2 years ago just plum knock jack for a loop trying to take the doe until he made contact. And yes, I as well use waterfowl decoys and turkey also.