There may be no better time all season to use a doe decoy than during the rut.
Decoys are an extremely effective tool to use to bring bucks within range of your set up. I've watched mature bucks walk completely across a field just to scent-check a doe decoy before continuing on to look for other does that may also be in heat elsewhere.
Buck decoys are the tool of choice during the pre-rut because once does go into heat, a doe is all any buck is looking for. With a properly set doe decoy, you will be giving them just what they are looking for.
The first rule of using a doe decoy effectively during the rut it to watch your wind. You must set your decoy upwind of your stand or blind. Be sure to position stands on your property to allow for multiple winds from different directions so you don't limit yourself when a wind comes from a direction you weren't expecting.
Deer will always circle a decoy to scent check it. If your decoy is downwind, it will smell you, long before it ever gets a chance to smell the decoy.
Another very important rule of using a doe decoy is the direction your decoy is facing. Bucks approach decoys from the rear to allow them a good scent check before advancing or moving on. The last thing you want is your decoy facing you since that will put the bucks eyes in your direction as well.
With this in mind, place your doe decoy broadside, or better yet, quartering away. This will cause the buck to approach between your stand and the doe decoy while focusing its eyes away from you.
More from Wide Open Spaces:
Make sure to place your doe decoy 20 to 25 yards away from you, in a clearing. You want to make sure that the decoy is easily seen from a long ways away. If you see a buck off in the distance that doesn't see your decoy, a few well placed bleats or even a grunt might get his attention. Then just sit back and let the doe decoy do the rest.
When full rut is in swing, I will even sprinkle several drops of doe estrus behind the decoy just to add a little more realism to the picture I'm trying to paint
Good luck out there this year, especially if this is your first year trying a decoy.