Friday, February 19, 2010

Fun Fact Friday - Which Came First?

Yes, kids, it's time we had that 'little talk'. When we were in the Poultry and Rabbit building at the fair, there was an entire wall of educationalish FFA artwork. Some of this revolved around the reproductive process of chickens.
Yeah. Lori and I just didn't get it, exactly. There were lots of snaky tubes, and pipe cleaners glued to cardboard, and it just wasn't making much sense.

And remember, if I find something disturbingly intriguing, you're ALL going to learn about it. And there are some things you can't un-learn, so it's not like doing a somersault or riding a bike. Turn back now if knowing this means you'll never be able to eat eggs again. I will not bear the responsibility for this, nor will I abide another toe. If you don't think you can handle it, go check out this post instead.

But really, how do chickens 'do it'? It sounds like a bad Mister Wizard question from my youth.
Like other reproductive systems, it starts with ovaries. However, chickens, while born with two, develop a 'dominant' ovary. This is the one that starts all the egg-laying. In fact, several of the chickens at the fair had eggs in their cages. That's one of those things that just happens, and if memory serves, it happens about 5.5 times a week. This egg-laying cycle is referred to as a 'clutch'. Chickens run on some weird internal clock, that allows them to produce an egg in just over a day, but once it gets to be 3 pm, no eggs. This ends the cycle, creates a break of a day, and then the hen starts laying again, creating a new clutch.

I don't know if Daylight Savings Time factors into this at all.
Hens have about two years of productive laying time in their lives, after which they become soup fodder. Egg formation itself starts when the ovary produces the yolk, with its runny, yolky center, a single cell. The outer membranes and layers get added as the egg passes through the chicken, from the infundibulum (or 'the funnelly bit'), and then through the magnum (or 'the Sellecky bit'). The Sellecky bit is responsible for the secretion of the albumen, or egg white, and on a good day, can encompass two yolks at a time. Magnum, indeed!
Then we move on into the isthmus ('the membrane-y bit') and into the shell gland. What? I didn't figure that one needed a scientific renaming.
Then, and only then, does the egg pass into the vagina. I can't type the word without hearing Phil Hartman as Charlton Heston. However, avian vaginas differ from their mammalian counterpart in this area. Between the shell gland and vagina, chickens (and other birds) have sperm host glands. Hens can maintain a rooster's sperm at body temperature, allowing it to remain viable for up to two weeks inside the vagina. Each time an egg squeezes through the shell gland into the vagina, sperm is expressed back into the earlier stages of egg development, each egg fertilizing its next sibling. Except for the first egg, I guess.

So how does the sperm get there?
Sweet, sweet, chicken lovin', that's how. When chickens mate, the rooster presses his 'sexual opening' ('the penis-y bit') against that of the female by mounting her, flapping his wings and biting the hen's neck to maintain his balance. The male's sperm enters the female's sexual opening (cloaca) during this time. After entering the cloaca of the female, the sperm, containing the male's genetic information, travels up the oviduct to the sperm host glands where it awaits the next egg.

Don't you feel better for knowing this? I know I do. Omelet, anyone?

A special thank you to Dr. Thomas Caceci, without whose graphic depiction of the avian reproductive system today's fun facts would not have been possible.

16 comments:

MJenks said...

Roosters (and drake ducks, as well...haven't checked on other birds) will actually bite the neck of their hen in order to not fall off during copulation.

And, infundibulum is kind of a funny word. It means "intrument inside the butt"...but "infundi" means funnel.

Selleck-y part...tee hee.

Some day, I'm going to man up enough to tell the story of why I can't eat eggs anymore. It comes from grad school. There is much death and destruction involved. Really.

LiLu said...

Awwww, Phil Hartman nostalgia for the win.

Bev said...

Note to self: do not visit Elliott's blog at lunchtime any more.

Though this really was an eggcellent post.

What?! I had to!

MJenks said...

Better than it being eggscrement.

Bev said...

Eggzactly, Jenks!

Elliott said...

Oh, you kids!

Melissa said...

I only have three words:

Cow and Chicken!

Hee!

(okay, four)

Amber Tidd Murphy said...

I like my vagina, too!

calicobebop said...

Wow. Never in a million years did I think I'd be at home on a Friday night reading about chicken sex.

Mmmm... deviled eggs...

Elliott said...

Melissa, considered just cropping out Chicken, but how can you NOT love Cow?

But Amber, do you like Charlton Heston's vagina?

Calico, this is the life, isn't it?

And 'mmmm...deviled eggs...' indeed.

And Mjenks, I thought I could let this go, but I just can't. I have an instrument inside my butt, too. I think it's a wind instrument...

dogimo said...

See, I just must have misunderstood or something about bird sex. They do it just like we do it! I thought it was some weird deal like most fish, where the egg is laid first and fertilized after.

I'm so glad! I always felt so bad for birds!

Wait, not all birds. I mean, eagle sex with its stereotypical romantic death-dive is well-known and well-documented.

I guess I thought it was just chickens or other less-adventurous ground-bound fowl, who went the external fertilization route. Man, where the heck did I even get that idea?

Thanks for setting me straight, Elliott.

KLo said...

My friend was telling me a couple of weeks ago that eggs come "from the same hole as chicken s***", and I didn't believe him. How fortunate (and karmic) I am to have found the whole (THE WHOLLLLE : )) story of chicken reproduction ... thank you : )

Elliott said...

Dogimo - I think I had the same misunderstanding, back when I thought about it (which wasn't very often), and I stopped giving it any thought until we saw the bad FFA posters. After doing my research, they may very well have been good posters, but really, if someone told you to accept blindly that that third picture is all inside of a chicken, would you believe them?

KLo, glad I could be of service. I'm all about learning new things, especially if we can dispel the myth that new food and used food come from the same place.

Which brings up the whole concept of sausage casings...better not to think about that, I suppose.

tracey said...

As a nerd, I have to say I loved this post. Not a settence I thought I'd ever type relating to bird sex, but the "sellecky part" sold me & and the phrase "Sweet, sweet, chicken lovin'" was icing on the cake.

Also digging the flock of seagulls look on those chickens in the second picture. If I ever decide to get all rural, that's the birds I want.

Elliott said...

I'm all about the fancy chickens, and if we ever "decide to get all rural", as you so perfectly phrased it, I will have fancy chickens.

Nej said...

I just got the "chicken sex" talk. It's a shame when we kids have to get this talk online from blogs, and not from our parents. What is this world coming to?? :-) :-)

Be nice and share!

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