The handful of times we've incubated eggs in the past, we've basically "followed the recipe." We set the eggs for the right amount of time at the prescribed temperature and humidity, turned the eggs as directed, and raised the humidity when it was time. We made a few tweaks along the way based on what I read and our own observations, but we didn't know why we did what we did, particularly when it comes to humidity. Still, we've had good luck with respectable hatch rates. But as I've come to understand a little more about what's going on with the egg, especially during those first 14 days, I decided to approach it a little differently. So my eight-year-old daughter and I are doing a bit of a science project together on our current batch of incubated eggs. Last Sunday, we weighed the eggs trays (4 @ 70 grams each = 280 grams), and then we weighed all 48 eggs in the trays (a total of 965 grams - 280 grams = 685 grams of eggs). We decided our target for the eggs at lockdown (based on our research) is a 13% loss of weight (which would be 595 grams, rounded to the nearest 5 grams, the accuracy of our scale). So we made a graph. I drew it on the computer, but printed it out because I thought it would be more meaningful to my daughter if she was plotting things by hand. She found 685 grams at day zero and plotted the point. Then she found 595 at day 14, and she plotted that point, too. The temperature has been 99.5f and the humidity has ranged between 38% and 42%. We re-weighed today, one week later, and found the total weight of the eggs (after subtracting the tray weight) was 650 grams. I was surprised -- I expected more weight loss. But she plotted 650 grams at day 7, and connected the points. It was clear to both of us that we would need to increase the rate of weigh loss to reach our day 14 goal. In a way, I'm pleased that an adjustment was required. I think it makes for a more satisfying project for her (for me, too), especially if we get a good hatch rate. Anyway, I wanted to share our project and how we're approaching it. I'm also open to any input, especially if there's something I've overlooked or am misunderstanding. My one concern is that if there are eggs that aren't viable, could they be throwing off the weight. I've never candled as it seems disruptive to pull out all 48 eggs individually, and I can't really seem to tell anything anyway with the ones I've tried. So I haven't made any adjustments for bad eggs.