It's been some years since I incubated eggs. I am gonna build a new smaller, simpler incubator this time. My hatch rate was always pretty good but, my incubator was a complicated build. I don't want to spend as much time with the bells-n-whistles this time. This incubator will be forced air. And, it is obvious that the developing chicks need a steady supply of oxygen. In the past, I allowed as much outside air in to the point of not making it difficult to keep a constant temperature inside the incubator Does anyone here have a simpler way of knowing just how much air to allow in without jeopardizing the chicks? Yet, making it making it easy to keep the temperature perfect? How are you guys regulating y'alls air?.