If you have a bator with no fan installed in it, you can make and install one yourself by using a computer fan and a 12v charger from an old toy or a cordless phone.
Go back to the first few pages of this thread and search how to make your own fan.
Before I got my Sportsman, I used still-air stryo. bators and found that they improved greatly with three things added to them:
(1) i made an expansion coller out of stryofoam so that I could raise the height of my top up 2-3 inches
(2) Add the homemade fan and it helped keep the temps and humidity stable
(3) put the bator bottom up on some strips of wood so that the bottomside gets clear ventilation, improved circulation also.