Richard Sweetnam, age 8, of Huntsville, Alabama, for his question:
Why does a chicken have a gizzard?
A chicken has no teeth to chew and for her size she needs a lot of food. She is on the go from sunrise to sunset and her busy day uses up a lot of energy. This energy comes from the seeds, grains and other scraps of food she eats. With no teeth, she must have another way to chomp up her diet into digestible portions. This is why she has a gizzard.
Many cooks chop up the gizzard and boil it to make gravy to go with the roast chicken. It is made of very tough muscle fibers but, when properly cooked, it adds a nice savory flavor to the gravy. The gizzard is tough because the chicken uses it for very tough work. It opens and closes somewhat like a fierce little fist and mashes up seeds, grains and other chicken food. Sometimes it needs help and the chicken swallows a few gritty pebbles. As the gizzard fist opens and closes, the sharp stones make extra cuts and slices in the tough food.
Chances are, the farmer feeds the chicken one or maybe two main meals every day. But she is a bird and all birds prefer to eat snacks all the time. She finishes the helping of corn that was given to her. Then she returns to her all day job of scratching the dirt and pecking up scraps. Our bodies have digestive systems to cope with three balanced meals a day. The chicken needs a very different digestive system to cope with her endless snacks.
Having no teeth, she swallows each bite whole. Bit by bit it goes down her gullet where there is a pouch called the crop. There it is mixed with moisture and perhaps stored for a while. Then the food passes on down to the chicken's stomach. There it is doused with strong digestive juices. The mushy mass then squeezes into the gizzard. The tough walls of the little fist mash up the mixture of food and digestive juices. The jagged gravel helps to tear up the toughest fragments.
When the job is done, the soggy pulp is sent to the long, winding intestine. The usable portions are taken through tiny doors and dissolved in the blood. The chicken's little heart pumps the blood and it delivers the digested food around her body. The chicken eats extra tough food. Birds that eat insects and softer foods have smaller gizzards. Grasshoppers and certain other creatures also have gizzards. The earthworm has a tiny gizzard and he swallows tiny grains of sand that help it to chomp up his food.
We know that the body needs food. And you would think that it can use it just as we eat it from the plate. This is not so. The food we eat must be mashed up and mixed with digestive juices that break up and change its chemicals. The chicken must also digest the food she eats. And the chomping up job is done by her gizzard.