Are you bow hunting, gun hunting? Is the corn still standing or cut?

If you are set up 20' from the scrapes, you are probably a tad close. I'd hunt it again ... then maybe find a downwind spot to move your setup. Position yourself so you catch them coming to that spot, rather than being right on top of em when they get there. Especially if the corn is still standing.

If you are gun hunting, obviously you can afford a little more distance than bow.