Candling Undecided Eggs - 12 days old

Today is Monday March 9th, the eggs have been incubating for 12 days.  On Friday the 6th, students found 10 good eggs, 2 dead eggs (with blood rings) and 5 eggs that we weren't sure about.

Here are what two students wrote about candling eggs today:

"We were able to tell if the eggs were good or bad by candling the egg.  If we were able to see blood vessels and a dark spot that meant the embryo was in there and growing, but if there was a ring in it the embryo was dead.  If there was nothing to see then the egg was probably not fertilized.  In class we discovered that five eggs were useless because two were dead with a ring on it and the rest weren't showing any improvement."
- Daniela

"Today we candled eggs, 10 of the eggs are still alive and growing great.  The other 7 eggs are not growing, 2 of them have bloodrings from bacteria.  We also cracked one of the [bloodring] eggs open to see if you could see a growing embryo, but no!! The embryo never started growing, all there was was yolk!"
- Praynicia

This egg had a "blood ring" which means the embryo died and bacteria create a red ring around the inside of the egg. We broke this egg open and you can see the red inside the shell.  The bacteria ate the yolk membrane so the yolk was mixed in with the egg white.