Newbie questions

[Criticalicious]

I am incubating 7 dark brown BCM eggs in a Brinsea II Advanced, set two weeks ago in the evening. I have searched Google and these forums for awhile and can't seem to find answers to some basic questions about candling.

1. Will the air cell grow if there's no embryo? I've been marking what I think are air cells on the large end of the eggs and it's been growing on all the eggs, but I can't see embryos in half the eggs (which I've read can be normal for dark eggs).

2. Is it possible my eggs are a couple days behind schedule? The ones where I can find the embryo look more like Day 10 pictures than Day 14 pictures. Should I go ahead and lockdown on Day 18 or candle again and decide based on that?

3. How is it I could clearly see something in an egg one day (I marked an eye or a heart on the shell with pencil), and then not find it two days later? Do they move around closer to the shell and then towards the yolk as they develop?

 

[sylviethecochin]

1. Will the air cell grow if there's no embryo? I've been marking what I think are air cells on the large end of the eggs and it's been growing on all the eggs, but I can't see embryos in half the eggs (which I've read can be normal for dark eggs).

Of course! Don't you find an airspace in your hard-boiled eggs? (I sincerely hope those don't have embryos in them.)

2. Is it possible my eggs are a couple days behind schedule? The ones where I can find the embryo look more like Day 10 pictures than Day 14 pictures. Should I go ahead and lockdown on Day 18 or candle again and decide based on that?

Candling's not an exact science, and they aren't all going to look like the pictures. I would candle at day eighteen, though. Just in case.

You could be miscounting the days and it's actually day thirteen (it happens more often than you might think, but day one, for a few reasons, does not count as day one, but day zero.)

3. How is it I could clearly see something in an egg one day (I marked an eye or a heart on the shell with pencil), and then not find it two days later? Do they move around closer to the shell and then towards the yolk as they develop?

They move around, and they also develop some mesodermal tissue (which basically means everything between the skin and the gut) which hides the heart especially. It's really cool watching those little hearts flutter, though, isn't it?