Well I can definately sympathize with anyone who's had eggs go bad. Last year, our first and only clutch went completely bad. by this far into their incubation, they were already foul and green/orange. Then this year, my first clutch went bad after my stupid hovabator spiked their temp. I got a crash-couse in Correct incubator building, and managed to set the inc. up before these guys arrived; now I have two happy clutches baking in it
That first clutch though last year, I had done everything right. One egg held on for a longer time and in it was a deformed fetus that looked healhy except for being undersized and crimped/overgrown in some spots and squished-in in others.