My Black Cochin Morgan, 11 months old, just went broody today for the THIRD time! I heard Cochins were broody fiends, but this is getting ridiculous.
I had heard that you can break a broody real quick by dunking them into cold water or, if it's handy, a snow bank. Usually I break a broody in less than three days by using the wire cage method, but it takes time. So I tried the cold water dunk on Morgan. The theory is you want to cool down the broody's body temperature. Well, after two separate dunks, one for one minute, and the second for five minutes after the first one didn't phase her, Morgan wasn't any less broody. So much for that method.
My advice to you is to set up a cage with an open mesh floor, no bedding at all, and put a fan on the floor so it blows gently on her under-side. This will counter the broody urge better than anything, cooling her and keeping air flowing under her. Usually my broodies are broken by the third day. The test to see if they got un-broody is to turn them loose and see if they head right for a nest box. If they do, it's back into the broody cage for another day.
Morgan will spend the night in the garage with a fan blowing under her and tomorrow, she will spend the day in the broody cage, sans fan, inside the pen with her flock mates to keep her company and to discourage the urge to be alone in a dark place. Two days and two nights usually does it and she's back to normal. Works every time for me. Hope this works for you, too, should you choose this method.