Yesterday afternoon day 20, i was pretty discouraged thinking we werent going to have any hatch this time...I had discovered one of dear grandsons had turned the heat up to 108 for several hours around day 12, but kept on hoping and praying for the best. Last night we started hearing cheeps and noticed three pips, went to bed and woke up hoping for hatches, but found 10 pips and 1 zipped. After work only one had hatched by 3 PM...by 8 PM tonight a total of 9 have hatched,one is half way out, three are pipped and waiting for action on the other 9. It seems like it is taking longer this time for them to hatch out. the shells are harder for the chicks to get through or something. How many hours should I wait before it is absolutely needful to help? Does any one ever change the feed to a lower calcium level before setting any eggs?