Tuesday, October 30, 2012

Chicken eggs

Today we have a guest post by New Hampshire teenager Molly Barlow, who has been raising chickens for nearly half her life. I met Molly (2nd image) this past summer while she was visiting her grandparents in Florida. She told me about how chicken's legs and yolk color are connected and I was so impressed that I asked her to put it into writing so I could share it. She also ingratiated herself by identifying the chicken skeleton in my museum as soon as she saw  it!

There are lots of things most people don't know about eggs. Most people buy the Grade-A, perfectly shaped, spotless brown or white eggs from whatever grocery store they go to, and are completely unaware that other sizes, shapes, and colors exist. There are speckled eggs, round eggs, oblong eggs, nearly black eggs, blue eggs, green eggs, pink eggs, mini eggs, gigantic eggs...the list goes on. Different chickens lay different eggs. Even 2 birds of the same breed lay slightly different eggs. At most egg farms, more than half the eggs are thrown out or put in lower grades - B or C - because they aren't quite perfect enough to go on store shelves (too small, too large, a speckle, a double yolk, or some other "abnormality"). The thing is, these "abnormalities" are normal. I mean, if you think about it, how likely is it that every egg a chicken produces would be perfect? So I'm writing this to give you a little more information on this rather interesting subject.

Let's go from the inside out, and start with the yolk. The yellow blob in the center. Once I met a person who didn't know what the yolk was called. Anyhow, the yolk is what feeds the chick while it's growing in the egg. And no, not every egg has a chick in it, only eggs that have been fertilized by roosters can produce a chick, and only if they are kept at a specific temperature for 21 days, and even then only about 60% of eggs hatch, and after that there are any number of problems that can arise if the chicks aren't given proper care – but I digress. The yolk is the main food source for the chick. It contains all the fats and a little less than half the protein. The yolk's color ranges from bright yellow to gold to a paler color usually seen in grocery store eggs. The color doesn't affect the nutritional value of the egg (though it is generally agreed that brighter, "healthier" colored eggs taste better), it merely depends on what the bird is fed: hens with more corn in their diet produce brighter yolks, and hens with more grains in their diets produce paler ones. But why yellow? This is one of the more intriguing facts. The color itself, the yellow pigment, comes from the chickens legs. Yep, you read that right. Most hens hatch with bright yellow-orange legs, and as they lay more and more eggs, this color slowly bleaches out. However, the color can be replenished by the sun – which is why factory chickens, who spend their entire lives in small cages, stop laying less than 2 years after they start, and free-range hens, who get lots of sunlight, continue to lay into and sometimes beyond their 3rd year of maturity. But what about hens with black legs? Turns out, they still have this yellow pigment, it's just overruled by the dominant black pigment.

Next up is the egg white, or albumen (al-byoo-men). Except no one calls it the albumen. I don't know why, it's such a cool word. So, the albumen contains the rest of the protein in the egg. When the egg is laid, the albumen contains carbon dioxide, making it white, opaque, and cloudy. As the egg ages, the carbon dioxide escapes through the pores of the shell and the albumen becomes clearer and thinner. This is one of the reasons why when you try to fry an old egg it runs all over the pan. Around the albumen are the inner and out membranes. Why 2? Because right after the egg is laid and starts to cool off, a little pocket of air forms at the wide end of the egg between the two membranes. This is so the chick can breath as it's developing; the air sack becomes a channel, getting fresh air through the pores in the shell to the chick. This is also why eggs are always placed pointy-end down in the egg carton – with no chick using the air in the sack, it slowly grows. If the eggs are in the carton pointy-end up with the air sack at the bottom, the air sack would grow faster because air rises, and consequently the egg would go bad faster. One more neat thing about air sacks: older eggs, having larger air sacks, will float in water, while newer ones sink.

Last, but most certainly not least, is the eggshell. The shell is made mostly of calcium carbonate, and is covered with pores, allowing air to get into the previously mentioned air sack. But couldn't germs get inside, then? Nope. The egg is laid covered with a thin, pretty much invisible protective covering called the bloom, or cuticle, which keeps out bacteria and also keeps in moisture. Often when eggs are collected there's dirt and other unpleasant stuff on the shell – this is cleaned off, of course. But some factory farms clean their eggs a little too well, and the cuticle is wiped right off, letting in bacteria. The shell of an egg is truly brilliant. It is shaped in two convex arches, which give it incredible strength. If you drop an egg, and it lands on one of its ends instead of its side, it is highly unlikely it will break. The television show "That's Incredible" ran a segment in which eggs were dropped 300' from a helicopter – and some of them didn't break. The strength and thickness of a shell still varies, of course. Free-range birds with access to more food and sunlight usually produce stronger shells than factory birds. I remember when I first got chickens at age 7; when they started laying 8 months later, I tried to crack one of their eggs to fry. I was used to eating store-bought eggs until then, and they usually only require a couple light taps to crack. It took me several tries to crack the egg from from my chickens.

And the egg itself. Size differences come from a lot of different factors.When a hen first starts laying, her eggs are usually smaller. And believe it or not, there are different sized chickens. There's the standard; the bantam, which is between 3/4 and 1/2 the size of the standard; and the rarer jumbo, or giant, usually about twice the size of a standard. The standard lays medium to large eggs, the bantam peewee to small, and the giant lays X to XX-large and jumbo. And contrary to what may seem logical, the bantams tend to lay the strongest eggs. Lastly, there's the color of the shell. In doing a little extra research while writing this, I stumbled across the myth that the color of the shell has something to do with the nutritional value of the egg. What? No! The color of the egg is just that – the color. But it's still pretty cool. You can usually determine what color egg a hen will lay by looking at – get this – her earlobe. Hens with white earlobes will lay white eggs, hens with slightly tinted blue or pink earlobes will lay tinted eggs, and hens with the traditional red earlobes lay brown eggs, though there are a few exceptions to this rule. The Ameraucana has red earlobes but lays blue eggs in various shades. The many, many different breeds lay so many different colored eggs: 
  • The Barvelder lays eggs with a unique copper color. 
  • The Catalana lays pinkish eggs. 
  • The Penedesenca lays very dark brown eggs. 
  • The Cochin lays lovely speckled brown eggs. 
  • The Maran lays deep reddish-brown eggs. 
  • The "easter-egger" lays pastel green and blue eggs.
Chickens are truly fascinating creatures. Some people say that they are mean, stupid egg machines for us to eat, but after having chickens for half my life, I must insist those people are wrong. Sure, there are a few ornery ones, and some that aren't very bright, but every chicken I've ever met or owned has a personality. Some are friendly, some are shy, some are talkative, some are quiet, but once you get to know them they can become lifelong friends. Because they are a lot like people. They have good memories for human faces and they definitely have feelings.

Sources: The Chicken Health Handbook by Gail Damerow, Raising Poultry Successfully by Will Graves, Storey's Illustrated Guide to Poultry Breeds by Carol Ekarius, and various knowledgeable chicken people and friends. Images courtesy of Molly Barlow.
For more about eggs, 
start here.

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