I set 7 eggs... 4 Cochin, 2 Spitzhauben, 1 Astralorp. All 4 Cochins hatched but one with splay leg on one limb. None of the big eggs. I just ordered Light Sussex and Wheaten Penedesenca hatching eggs to do just big eggs this time. There HAS to be something about egg size. I can hatch the heck out of Bantams, Quail, and ducks. But never in all my small attempts have I gotten big chicken eggs to hatch. Have only ever tried 2-4 at a time though. I ordered 24. The reason I say there is something different... because I will get 100% on Bantams and nothing out of the big eggs on day 21. I leave them until day 23 just to be sure. I broke open these last ones to see. One Spitzhauben never started, tossed it at day 14. The other quit around day 14. The Astralorp was fully developed but never absorbed the yolk or pipped. But 100% on the cochins!! I don't get it. Any advice or ideas? I use a Hovabator. It's always been successful for my Bantams. Now I want eating eggs so I went with standards, with 2 Bantam Cochins for fun. Is it a temp thing? I managed 99.5 whole way through this last hatch. Do bigger eggs need more? Humidity was fine besides the time 6 days in when it went dry because my husband turned on the dehumidifier in the basement, though that crisis was solved quickly. I was thinking of aiming for a flat 100 degrees. Or would they want less because the egg is closer to the heating element due to size? So a flat 99? Every other time was a steady 99.5 and nothing big hatched. Always fully developed but not coming out, for the most part. Help! I have 3 days to make a new plan!