[jobson336]

hi, i have a hen that is consistantly laying double yokers and my 8 year old daughter asked does that mean if we had a 'daddy hen' she would have twins in that egg?
i said i dont know i will ask everyone on the chicken chat room!
can anyone answer?
thanks

[Casey76]

Well,, while in theory there may be two viable embryos (one on each yolk) in practise there is no room in the shell for two embryos to develop.

If you are incubating or brooding, the eggs shold be candled, and double yolkers should be discarded.

[wolverine]

just out of interest is there any reason that an egg can't be cracked open into a kind of fake egg that was big enough for both embryos and perhaps a bit of extra White from another egg and just let them develop in there? it would be good to have them develope in a see through thing so you could see the development day by day.
does a chick have to grow in it's own egg for any reason?

[8doubles]

If i remember my 5th grade biology right ( a long time ago ) the chick develops from the fertilised white which uses uses the egg yolk as food .
Abnormal eggs do not normally hatch or survive if they do hatch.
Full marks to the daughter for asking.

[Casey76]

The embryo develops from the "blastoderm" (white spot) which is present on every yolk.

You can see this on normal eggs... if the blastoderm is small and possibly have an uneven edge the egg is not fertile.  However if the blastoderm looks like a target or has a bullseye appearance then it is fertile (and at that stage has gone through approx 3 days of growth - the time it takes for the fertilised ova to pass through the oviduct and have albumen and a shell formed around it before the egg is layed).

The albumen is mainly a buffer to protect the growing embryo from changes in temperature and from knocks.  The albumin slowly evaporates as the embyro is growing (which is why having controlled humidity is important, especially for forced air incubators).

[evie2]

I'm glad someone asked that question I've always wondered about double yokes

[Kate and her Ducks]

Slightly off the twins topic but some time ago when looking up candling I found a site that showed the development of a chick, day by day, with a window cut in the shell. Wish I could remember where. Will try and find it.

[Kate and her Ducks]

Haven't been able to find the one with the window but did find this one.

http://freshpics.blogspot.com/2007/05/stages-of-chick-embryo-development.html

It is bit grusome as an egg has been cracked on sequential days but it is very interesting.

[jobson336]

wow as always full and informative answers from you chicken experts out there, i will let my daughter know. thanks everyone

[wolverine]

Good photos but a bit mean onthe poor chick towards the end