Incubator need a fan?

[Gloryhound]

I made a wine cooler incubator, herpstat holds perfect 89 temps, Is a fan a must for one clutch? Do you think I can go to a mom/pop computer store and have em wire me one up?

From everything I have read it is highly recommended as it keeps the temps in the enclosure all at the same temp and removes any cool or hot spots!