cooler incubator fans

Well I've started working on my incubator and I'm wondering if the fan I have is going to be enough to circulate the heat through out the cooler. I have an igloo max cold 152 quart cooler and 1 115vac fan. Should I add another fan or is one sufficient?

http://i231.photobucket.com/albums/e...rick/bator.jpg

should be fine. the fan's only purpose is to move enough air to help keep the temps the same throughout the incubator.