I just finished my first attempt at hatching .... with no success. There are a number of things I did wrong. I opened all of the eggs and found that they probably died around day 14-16. Anyways, I found this website that suggested retrofitting a still air incubator with a computer fan and a cell phone charger to cut the cost of buying a fan kit that cost over 40 dollars. I only spent $12. The fan that I got is very small 1.5" x 1.5" with an airflow of 7.7cfm How big are the fans normally in an incubator?