Brumation can last for 1 week to 5-6 months... All depends on the Beardie itself. Brumation doesnt necassarily mean "sleep" either (although 99% of the time they do). They can just lower their energy cycle and eating habits tremendouosly and remain "sluggish" through out the winter months. Definetly if you reduce/lower their heat/light cycles from a 10 or 12 hour on/off, every 2 weeks reduce by 2 hours, until 6-8 hour on for 2 months. Thats my remedy, I do not believe in "Shutting them down", I personally and self consiously dont like knowing my Beardies are living off of their own body fat. I offer them butterworms every other day (a naturally high calcium worm & fatty enzymes) you can purchase them resonably at http://www.MulberryFarms.com
I would not be worried abouot your beardie, it's their natural instinct to do what their bodies instruct them to do. I have never had a problem with "not brumating" my males or females. I just reduce their cycles. I just produced 5 klutches of Orange Phase babies in klutches of 24-28 eggs each in result of.
www.AtlantaBeardedDragons.com