Double Yolker Eggs And Twins

Posted October 24, 201113 yr

So, I have this large yf grey hen ( bred by forum member Liv ) and she's paired up with a violet spangle cock ( loaned by forum member RobD )

YF grey hens sister was 12th at the Nationals.

............first egg the hen laid off the perch,

second egg the same.

Then I cut a larger hole in the nestbox as she was so big it seemed she wasnt happy going into the nestbox ( if she could fit )

Next egg was huge !! one inch long, like two eggs in a row. I thought fluke, a little weird and most likely a double yolker

...and today she laid her next egg...

another one exactly the same ...another one inch long egg, same shape and size and another double yolker

So here's a picture of the two D.Y. eggs next to a normal sized egg

Both the same size and shape as I said and both double yolk eggs

Candling ( note the two yolks showing in each of two eggs )

So, possibility of twins...............Most twins never survive as they run out of growing space. Twins are rare, so we dont get our hopes up for twins.

I have had twins make it to hatching and beyond before

http://forums.budgiebreeders.asn.au/index.php?showtopic=14683&hl=twins

Other double yolkers I have had

These are twins that didnt make it to hatching

and another

Note in the photo just above this the chicks were beginning to become deformed due to lack of space in the egg.

so the upshot of all this is........

TWINS rarely make it to hatching. Time will tell with these eggs.

ADDITIONAL INFO provided by forum member Dean_NZ

I think it's even more amazing when you know how budgies produce eggs. To save me writing it out, here is a quote:

Most birds have only one ovary and one oviduct. In early stages of embryonic development, each female bird has two ovaries; only the left one develops into a functional organ. In some birds, such as hawks, the right ovary and oviduct usually develop. A mature ovary looks like a cluster of grapes. and may contain up to 4,000 small ova which can develop into mature ova.

With fertilization, the ovum (egg) becomes a developing embryo

The embryo passes through the oviduct; typically takes about 24 hours (for passerines & most other birds)

The demand for calcium to make the egg shell is very high, and so the circulating levels of blood calcium in birds are greatly elevated compared to mammals, typically twice as much.

Source: Avian Reproduction

Here is a picture of the ovary which DOES explain visually how a double yolker would be possible (if two yolk 'buds' developed and released simultaneously instead of maturing one after the other). As you can see - the yolk is fertilised well before the egg begins even forming:

The process of encasing this yolk once released (ovulation) is here:

Here is some more info:

DOUBLE YOLK EGGS:
Double Yolkers appear when ovulation occurs too rapidly, or when one yolk somehow gets "lost" and is joined by the next yolk. Double yolkers may be by a pullet whose productive cycle is not yet well synchronized. They're occasionally laid by a heavy-breed hen, often as an inherited trait.

Source: Poultry help website

Because of the internal changes to the layout of the air sack etc and the lack of space, double yolkers rarely hatch successfully. I know of a few that were fertile, but died when they ran out of space, or perhaps the movement of one chick disrupted the yolk/amniotic sac of the other chick and killed it etc.

Also, they are twins, but they will be fraternal twins not identical Fraternal means they shared an egg but are from different embryos.

Edited February 9, 201213 yr by **KAZ**

October 24, 201113 yr

Wow, thanks for the photos Kaz.

Funnily enough I had quite a number of eggs like that this year and a few had air bubbles in them as well. I didn't candle them but just chucked them.

Next time if I get any more I will candle.

October 24, 201113 yr

Gosh Kaz those eggs are HUGE!!

Hope they hatch for you, i,d love to see the chicks, the parents look nice so the chicks should be too, would be a nice clutch if she continues to lay

October 25, 201113 yr

Author

Gosh Kaz those eggs are HUGE!!

Hope they hatch for you, i,d love to see the chicks, the parents look nice so the chicks should be too, would be a nice clutch if she continues to lay

They are bigger than most of my past twin eggs

October 25, 201113 yr

I have had the same, long like those and they have been fertile but seem to be dead in shell at hatching time. I have one at the moment fertile but hasn't hatched yet and I don't think it will.