Back to Nature (Published on TBNWeekly.com - March 29, 2007)
Grand Slam special: Two eggs, pancakes and sausage. Did you know that per capita
the average American eats close to 255 eggs a year?
|Illustration by Karen Mitchell Tremmel
|Birds eggs come in many sizes
and beautiful colors.
Besides the all American breakfast, consumers get their daily dose of eggs in
cakes, pasta, cereal and even some candy bars.
Currently Florida ranks No. 8 out of the top 10 egg producing states. According to
U.S. Department of Agriculture, American Egg Board, USAPEEC:
U.S. egg production during June 2006 was 6.56 billion table eggs. Total
U.S. egg production during 2005 was 76.98 billion table eggs.
In 2005: Per capita consumption reached 255.1. Per capita consumption is a
measure of total egg production divided by the total population. It does not
represent demand (USDA has recently adjusted data to reflect 2000 Census
So where do eggs come from? Birds lay eggs. Well of course, we know that birds lay
eggs, but how does an egg become an egg and how does an egg become a chicken. If
you are laughing about now while asking yourself that age old teaser, Which
comes first, the egg or the chicken? for the sake of argument, lets
assume there exists two birds, one male and one female. In many ways this process
is not that different from human beings.
Fertilization in any animal depends on production of eggs from the female and
sperm from the male. The female mammal produces an egg. That egg must be fertilized
by the sperm from a male to produce offspring. For most birds, copulation involves
a cloacal kiss, with the male on the females back and twisting
his tail under the females copulation typically lasts just a few
Dennis Chang, graduate student and HHMI predoctoral fellow at Harvard University,
has this to say about that:
Birds, like mammals, use internal fertilization. Many species of birds lack
a penis; instead, the males just has a genital opening (cloaca), which must be
positioned against the females genital opening (also called a cloaca) for
sperm transfer. Male chickens, however, do have a small penis to facilitate mating.
In any case, after copulation, which only lasts a few seconds, the sperm quickly
swim up the oviduct toward the ovary. The sperm can stay alive in the oviduct for
several weeks, ready to fertilize the next egg cell (oocyte) that appears.
After a yolk package is released it lingers there for about 20 minutes. If
sperm are present, then the egg cell is fertilized and becomes an embryo. But if no
sperm are around (that is, if the hen has not mated), then the egg still proceeds
down the assembly line of the oviduct. In this assembly line, albumen (egg white)
is added around the yolk, shell membranes are added, and the shell itself is
Finally, the complete egg is pushed through the vagina and out the cloaca.
If the egg has been fertilized, then the embryo inside has already divided several
times but remains a group of unspecialized cells. When the egg is incubated at
about 37 to 38 degrees C, the embryonic cells differentiate to form a chick, which
will hatch after 21 days.
The hens reproductive system can be divided into two major components:
the ovary and the oviduct. The ovary produces the egg yolk. The oviduct adds the
white, shell membranes, and shell to the yolk to complete egg formation.
Information Sheet 16º10, by Dr. Chris McDaniel, associate professor, Poultry
Science Department, Mississippi State University.
Female birds do not need a male to lay eggs. Unfertilized eggs are laid regardless
of whether there is a male present in the hen house. Although having grown up
raising chickens, those hens would stop laying if the rooster didnt crow, so
to speak. Every year or so it was necessary to purchase a new rooster to bring in
new blood, as well, to bring back a little romance for the pining hens. Most eggs
that reach the supermarket shelves are not fertilized.
Eggs come in all sorts of sizes, shapes and beautiful colors. If youre
traveling on spring break or this summer why not take a tour at one of these great
museums to observe birds up close, as well, bird egg collections: The Royal Ontario
Museums Gallery of Birds, Norfolk Museum, The Richter Museum of Natural
History, Finnish Museum of Natural History, Harvard Museum of Natural History.
There are always so many beautiful things to see and learn
Karen can be reached at MyMuddyPawsStudio@gmail.com.