My last hatch went bad, only one spontaneous chick at day 23-24 I rescued some that had piped after several piped ones had died in the shell. I've heard so much back and forth on humidity. The room I use has 60% humidity typically....so that would be my base point. It appears my barnevelder and wellsummers drowned....while my buff orphingtons all got so stuck they died in shell as did the blue andulusan...I did sucessfully rescue a BO for a few hours, and have 2 rescued spotted sussex plus 1 which hatched well immediately....no I waited over 24 hours before I briefly opened bator grabbed two eggs removed....dead...but I had pips after 3-4 died stuck in shells....then the rescue mission. On post mortum....all in hatcher a hovabator with fan had chicks fully developed but 2...these 2 likely just short of full development. My bator takes less than 10 minutes to recover to 75% humidity and temp....I've checked with a watch and 2 meters.....differet eggs, different sellers all shipped. I had nearly 100% developement of my orpingtons, sussex and andulusians, wellsummer and barnevelder. Zero percent on amerecanas....purchased from 3 sources!!!!! any thoughts. I have 4 eggs coming off today americana another try...these 4 developed out of a dozen from a 4th seller....all other varities have developed well. Any suggestions....also best humidity to hatch at, I've heard a couple of numbers. mary