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Egg-Citing Facts
By Linda | October 17, 2008
Eggs are truly a wonder of nature. It takes just a day for a chicken to produce one of these perfectly packaged little miracles! Did you ever wonder how the shell gets on the egg? I sure did. Here’s what Sciencejunkies found out…
First, some common questions and answers about chicken egg production.
1. How often do chickens (hens) lay eggs?
Answer: A healthy chicken will lay about one egg a day. The frequency at which a hen lays her eggs is most affected by daylight patterns. A hen will lay more frequently when the days are longer. Commercial egg farms will often use artificial lights to maximize egg production. In ideal conditions, a hen can produce a new egg every 26 hours.
2. Does a chicken need to mate with a rooster to lay eggs?
Answer: No. A chicken will produce eggs regardless of whether she has access to a rooster that can fertilize them. Of course, the egg must be fertilized by a rooster in order for it to develop into a chick. Most of the eggs we eat that come from the grocery store have not been fertilized.
3. What determines the color of the eggshell?
Answer: Different breeds of birds lay different colored eggs. Generally, brown hens lay brown eggs and white hens lay white eggs. There is no nutritional or flavor difference between a brown egg and a white egg.
4. At what age can a hen begin to lay eggs?
Answer: Hens begin laying at about 18 to 20 weeks of age.
5. At what age does a chicken stop laying eggs?
Answer: As far as commercial egg producers are concerned, a hen’s peak egg production period ends when the bird is between 100 and 130 weeks of age (around 2 - 2.5 years old). A chicken’s egg production capacity continues to decline with age after this point. A backyard hen can live to be 20+ years old!
6. What determines the size of an egg?
Answer: The size of the egg is mostly dependant on the age of the hen. Older birds generally lay larger eggs. Other variables affecting egg size are the breed of the bird and diet.
At 500x magnification, the structure of an eggshell is revealed as a tangled network of mineralized fibers
An egg actually grows the shell around itself by means of a process similar to that of bone and seashell growth.
Around the egg is a membrane, and evenly spaced on the membrane are points where columns of calcite (a form of calcium carbonate) form. These columns stack together side by side to form the shell.
The calcite is basically floating in solution around the shell, and it deposits on the shell like a forming crystal. The egg grows its own shell!
And here is some Egg-cellent Egg Trivia…
- A lot goes into an egg. The hen must eat 4 pounds of feed to make a dozen eggs.
- Occasionally, a hen will produce double-yolked eggs throughout her egg-laying career. It is rare, but not unheard of, for a young hen to produce an egg with no yolk at all.
- In the U.S., artificial color additives are not permitted in chicken feed. Yolk color depends on the diet of the hen. Feed containing yellow corn or alfalfa produces medium yellow yolks while feed containing wheat or barely produces lighter color yolks. Natural yellow-orange substances such as marigold petals may be added to light colored feeds to enhance the yolk color.
- About 280 million laying hens produce some 60 billion eggs each year in the United States. That’s roughly one hen for every man, women and child in the country.
- Chickens came to the New World with Spanish and Portuguese explorers around 1500 - or did they?
- An egg shell may have as many as 17,000 tiny pores over its surface.
- Eggs are placed in their cartons large end up to keep the air cell in place and the yolk centered.
- The world’s largest single (verified) chicken egg weighed in at a bit under 6 oz - A recent claim is being investigated of a Cuban chicken named TiTi that laid an egg weighing 6.34 oz (.35 ounces heavier than the current record holder). To view a brief National Geographic clip on this Huevo Grande (Big Egg) CLICK HERE.
The Alberta (Canada) Egg Producers offer a web page featuring a dozen “Egg-Speriments” geared towards little scientists ages 3 to 7. To go there CLICK HERE
Topics: Animal Kingdom, Food Science, Nature, Science Factoids |
June 15th, 2009 at 2:24 pm
Hi I work at an Elementary school and I have a good question for you guys. Does a normal un fertalized and un developed egg weigh more or less, or even the same as a fully developed chick in the egg? Please get back to me !!!! I really appreciate it.
Amber