Kind of silly question

[Coyote]

My boss who really knows nothing about chickens really stumped me with this question-Will a fertile double yolk egg ever hatch out twins? Since I only hatch bantams and have never had a double yolk with them I was stumped. Can anyone help?

[faith valley]

I can not see how there would be enough room for 2 embryos to develop fully to hatching stage within one egg.  Plus, there is still only the one air cell and that air cell would need to supply oxygen to both chicks while they are internally pipped but before extenally pipping to gain taht extra oxygen.  I guess anything is possible, but it does not sound too likely.

[dak]

I am helping a friend who is a MD doing MRI research, and we are incubating double yolked eggs to various stages of development and then imaging.  I have had one make it to Day 19 with two viable chicks, but then I stopped development to mail to her.  Both heads were side by side near the air sac, so I guess hatching might have been a possibility.  

[Cloverleaf Farm]

It is possible, but they usually require help to hatch successfully.

[Beth C]

Rarely and with much help: http://www.youtube.com/watch?v=S1ZeEY-kt7A

[grisaboy]

They do sometimes hatch but they often grow together and you get something like this.

http://www.google.com/search?q=4+legged+chicken&hl=en&rlz=1G1GGLQ_ENUS295&prmd=ivnse&tbm=isch&tbo=u&source=univ&sa=X&ei=wxGbTf2iAY6ssAOym8COBA&ved=0CBgQsAQ&biw=1259&bih=456

curtis

[Beth C]

Oi!

[John]

This is not about an Ameraucana egg, but it fits the topic about a double yoke egg that came close to hatching twins today.  The thin shell of this jumbo Chantecler egg was cracked but they didn\'t hatch.  

[dak]

I have a double yolker in the incubator now, however only one embryo is developing.  I\'m going to let it run its course and see what happens with the extra yolk.