How to Tell a Fertile vs INfertile Egg (Pictures) - Page 5

Blastoderm
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A Blastoderm is the layer of cells formed at one pole of the yolky egg of birds. The yolk prevents the division from taking place through the egg, resulting in meroblastic cleavage during the many cleavage divisions. At the pole containing less yolk, the ovum divides and subdivides, forming the blastoderm, which gradually spreads around the yolk and forms the embryo. The blastoderm is comprised of two layers, the epiblast and the hypoblast, which enclose the fluid-filled blastocoel cavity. This embryonic stage is the avian equivalent of birds.

I may be understanding this wrong but sounds like that white dot is the start of the later division into a bullseye.

Yep, but it will only develop into the bigger white dot IF it is fertilized. Else it will stay small and tiny.

Term : blastodisc
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English  blastodisc  Embryo-forming area of egg prior to cleavage, also the early embryo or Teleostei comprising a disc of cells on the yolk. 
Forgive me Im going to look up cleavage now...oh boy lol
Just doing my best to understand this....no offense.
caroline

wow took some time to find this post of mine again....

So here is the best I could find out, by the sounds of it the egg would get fertilized hours before it is laid, therefore by the time we see it- it will show a bulls eye.

and here is more pictures;

http://images.google.com/imgres?imgurl=http://4hembryology.psu.edu/046.jpg&imgrefurl=http://4hembryology.psu.edu/fertile.html&h=267&w=400&sz=21&hl=en&start=25&um=1&tbnid=AxIvvDsOf2tpyM:&tbnh=83&tbnw=124&prev=/images%3Fq%3D%2Bfertilized%2Bpoultry%2Begg%26start%3D20%26ndsp%3D20%26um%3D1%26hl%3Den%26rls%3Dcom.microsoft:en-US%26sa%3DN

Oh I like this thanks for bringing it to the top again! My class will learn a lot. Now I'm going outside and snatching an egg from one of Whitey's nests,,, found out she's keeping two, and has 6 eggs in one and 8 in the other. I thought she wasn't laying! Now I have to find either Hershey's hidden nest or find out if she isn't laying at all right now. I know none in either nest are hers, they aren't green!

thanks for the photos and detailed explanation. i appreciate you posting this!

I really do learn something new every day!! Thank you.

Learning is fun! time consuming but fun 

Got a reply from a doctor/instructor I had emailed questions to last night during my study of the "white dot"

I will put the answers in body or the message.  Also see this web site for pictures and more details.

http://4hembryology.psu.edu/New%20site/fertilen.html

http://4hembryology.psu.edu/New%20site/femalen.html

http://4hembryology.psu.edu/New%20site/beginningn.html

Phillip J. Clauer
Senior Instructor
4-H Youth and Specialty Poultry

Department of Poultry Science
213 Henning Building
University Park, PA 16802-3501

814-863-8960 (office)
814-865-5691 (fax)
pclauer@psu.edu


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From: Caroline Parker [mailto:csparker@xplornet.com]
Sent: Tuesday, February 19, 2008 10:02 PM
To: pclauer@psu.edu
Subject: Egg Info



Hello, would you kindly answer me these questions?



1) A chicken egg is in no way shape or form fertilized if only a single dot is visible on the yolk?



** A non-fertile egg will only have the single female cell and look like a solid white spot.  The germinal spot on a fertile egg will be lighter and appear to be a donut shape, dark outer ring and light or clear center.



Compared to the obvious bulls eye of a definite fertilized egg?



2) Why do some eggs not show any dot at all?



** the Female cell is present on every yolk.  You just need to look and you will find it.



3) Are the eggs fertilized very early within the chicken hours before being laid?



*** Fertilization takes place as soon as the yolk drops into the reproductive tract.  About 23-30 hours prior to being laid.  That is how long it takes to develop an egg in the reproductive tract.  Since the reproductive tract is 105 degrees, if both cells are present, cells attach and begin to divide.  That is why they have a different appearance.  The germinal spot is still not a chick at this point.  It just contains both male and female cells and they have divide to prepare for incubation and development.  Once they are incubated they can develop into an embryo.



Thank you so much for your time doctor.



Caroline Parker

sorry to have to bump this again but now I am confused...

I wrote on a previous post today asking if my egg looked fertile. Because some said probably not, I cracked open another I was planning to incubate.

I do see a very very fine ring but not as pronounced as speckled hens pics.

Does this one look more promising???

Also are the red areas indicate some development of chick parts???

Thanks everyone and Speckled thanks so much for those pics!!!