Just hatched Heritage RIR's shipped eggs, 92% hatch rate. Incubation started in Brinsea ECO 20 at 100F . Cause of several species hatched at the same time I switched them to my homemade small cabinet bator after one week. Temp 99.5 humidity 50%. Lock down day 18 back in Brinsea ECO (easier to clean) humidity 70% at day 19. Temperature LOWERED to 98 at day 19. Hatch started day 20 all hatched within 24 hrs, just popped out of the shells, no struggling no drama, no helping. All strong and quiet healthy happy chicks. Eggs were in all kind of positions, "natural " in Brinsea, then "stand up" in homemade bator rocking on GQF turner, then again "natural" horizontal in Brinsea for hatch. No egg cartons or any other nonsence. I found out that I greatly improved my hatches lowering temperature about 2 degrees, and raising humidity as high as I can (70% or more) at lock down. No I did not invent it, commercial hatcheries do that all the time.