Why the need to cut eggs! impatience perhaps!
A good friend of mine cut his clutch of pied eggs last year, 7 eggs from het to het, of those 7 eggs, only one was a pied, he told me he cut at day 50, the sole pied stayed in its egg for 8 more days, the putrification smell that came from this clutch of rotting liquid with live babies swimming in this toxic soup ended up being lethal.
Of those 7 eggs, 5 babies died sitting in their egg, the two that finaly emerged including the pied ended up dying within a few days !?!
Could it of been a rookie mistake, could some of the blood vessels have been severed, could the embryonic liquid have rotted and consequently poisoned the hatchlings? could this have been prevented, perhaps had he waited for them to naturaly pip and emerge on their own would of prevented this mess.
He was so devastated and wanted to give up the hobby, I convinced him to continue and to just chalk it up as a learning curve!
He just naturaly hatched another 7 egg clutch from this same pairing and this time was rewarded with 4 perfect little pieds 
I feel there are lots of nightmarish experiences out there from cutting eggs and wanted to share this story, most will never come out and share their negative experiences, lesson learned, let mother nature take its course, they will hatch when ready 


