FINCHforum

So, a day after a clutch gone bad, my little CFW zebra hen Ivy laid another (enormous) egg!

But here's the strange part:


See what's missing?
No yolk!

How on earth is that possible?
I have a basic understanding of how eggs are formed. This photo explains it nicely:
http://tinyurl.com/mxxkznv

First, the ovary releases the yolk, then it goes down the oviduct where it's covered with albumin (egg whites), then the membranes and finally, the shell. Then about 24 hours after the yolk is released, an egg is laid.

So without a yolk, there's no core, so to speak. There's nothing to cover in albumin, membranes and shell!

How is this even possible??
I'm wondering if perhaps it's super tiny and I'm just not seeing it on candling?
If you look at that image linked above, you can see there are tiny yolks and much bigger ones. So maybe a tiny one was released accidentally?

I'm going to crack it open in a bit to explore; I'm leaving it for now so she lays some more. (Hopefully with yolks this time!)

Any idea what would cause this oddity?
Is there anything I can give her to correct it?

Edited to add: The egg was not as yellowish as it looks in that photo; it looked like a normal clear egg, just without a yolk.

Ah, I answered my own question!

There wasn't much info out there, but I was able to find the answer after a fair bit of searching.
It appears that sometimes a little bit of tissue or similar gets turned into an egg. So the little piece of tissue or particle or whatever serves as the "core" instead of the usual yolk.
And apparently this most often happens right at the start of a clutch - exactly what happened with Ivy - before everything is all in order.

They're called wind eggs, rooster eggs or.....wait for it...... "fart" eggs.

So there you go! There's your odd egg lesson for the day!

I also learned that you can occasionally see an egg within an egg! How cool is that?!
It would be even cooler if it hatched! But I imagine you'd need to crack away the outer egg first so the inner one could get air and pip properly.

Thank you for the egg lesson, very interesting. "Fart" eggs? Funny.

That's funny you're writing about this Mia. It was recently the talk of the town on a chicken/poultry site I belong to. It's very interesting! Double yolks are another thing that are very interesting though I'm not sure they would happen in finch eggs being so tiny. Wouldn't it be cool though!

Double yolk eggs in finches are not that unusual. Here's one thread from a while ago. http://www.finchforum.com/viewtopic.php ... +of+chicks
I posted a picture of double yolk egg chicks that died in shell (DIS)

debbie276 -- Wow! That's an incredible photo on the other thread.

I've had a few double yolked eggs. But I've never seen a dual development like that. And definitely no twin hatchings.

I had one where one chick survived; the other stopped developing pretty early in the game.
The parents killed the survivor by not feeding it. But he was normal as far as I could see in terms of size and appearance.

I never saw the remains in the nest (I did look). So I'm not sure what happened to the small one who was DIS. I don't know if it got eaten with the shell or whether it dried up and got covered in the nesting or what.

I bet one of Ivy's jumbo eggs would be perfect for a double yolked development! As I mentioned in another thread, her eggs are about 40% larger than normal.....

.....But the chick is NOT larger than normal.
Baby is a bit more stretched out right before hatching -- not a super tight ball like you normally see. And the air pocket was very large - about a third of the egg.
So I daresay you could likely swing a dual chick development in one of Ivy's eggs (and definitely if she had a larger-than-normal egg, as is usually the case for double yolks. A larger-than-normal Ivy egg would easily be twice the size of a normal egg.)

I've heard of rare dual-chick hatches. It must be something along those lines in order for it to be physically possible.

Those are huge eggs!!!!!!!! How?!?!

debbie276 That's amazing! I thought because they're so small that it couldn't happen. I guess nothing is impossible!
These are tiny eggs my zebra finches laid. It was two different finches, two years apart. I imagine they probably don't have yolks because they're so tiny. Now they're all dried out so to do an eggtopsy wouldn't tell me much. In a previous post Mia and I compared them to her giant eggs....which are amazing! Delray...How is right!!!

MiaCarter - glad you answered your own question. I was gearing up to type a response when I read the initial post. But you did all the work for me. ;)

delray wrote: Those are huge eggs!!!!!!!! How?!?!

Yeah, I've definitely wondered "how" myself!

If she was a human, she'd definitely be having C-sections! LOL

Ivy is a big girl. Not 1/3 larger, but definitely on the bigger end of the spectrum, so I imagine that helps. She's the size of some of the a larger zebra males that I've seen over the years.

I will say that it worries me, those large eggs. But I keep her supplied with lots of calcium. She's produced about a dozen now without trouble, so I guess that's just how her body is designed.

When I'd posted that egg photo originally, there was another member who'd given a link to a study on how birds with unattractive mates would produce larger eggs to compensate for that perceived genetic weakness (in animal world, unattractive = genetic weakness.)

So perhaps Molly Sue is ugly in the bird world?
Or it could be because he's old? (Though if fertility is any indicator, he's got an 80% fertility rate!)

@Corkysgirl -- I still can't get over those tiny eggs!
Indeed, I bet an eggtopsy wouldn't be any good, as the albumin yellows over time, as it dries up. So I imagine it would just be a dried up mess.

MiaCarter Yes I'm sure it's too late now to do an eggtopsy. They were so cute, I didn't want to break them.
It's amazing the fertility rate of Ivy's eggs. I don't think it's because of Molly Sue being ugly by any means. He's adorable! Maybe it is because of her size. It's very interesting really!