Last hatch, literally every speckled sussex hatched out before all the others made the first hatch out. Time before, it was literally every buff orpington What causes this? I don't have a very scientific incubator - handmade wooden with 3 racks - but I keep seeing this on all my hatches. Never saw this in my stryofoams. Can some one tell me why this happens? My eggs are all from our farm and right at the same age when they come in, The temp and humidity reading the same. I'm really curious about this. Thanks.