Ag 101: Curious Things You Want to Know about Chickens

chicken_headWho knew?! Chickens have ears! And the color of the earlobes determine the color of the chicken eggs?!  I can honestly say this is news to me.  The ears located on either side of the head are small holes that are hidden by feathers. The earlobes may stick out slightly and are located behind the eye and the waffle (the little bit of red wrinkly skin underneath the chin.)

White_earlobesThe color of the lobe can be a good predictor of the egg shell color that chicken lays.   Hens with white earlobes generally produce white eggs and hens with red earlobes generally produce brown eggs.   The egg shell color or pigment starts out white.  As the egg travels through the hens oviduct, which takes approximately 26 hours, color is deposited onto the shell. Because the pigmentation is not part of the actual shell but more like a painted outer covering, it can be washed off.  It can also be scratched off while the outer coating is still Red Earswet.  I’ve seen eggs that look marred or engraved…so they must have rubbed against wood chips or something rough in the nesting material.

I’ve always wondered why eggs come in a variety of colors…and does a different color mean better taste or some sort of unique quality?  A hen lays an average of 300 eggs per year. When it comes to the quality of the eggs you purchase, quality is sorted by exterior and interior quality of the eggs. There are 4 grades of eggs that have been established by the United States Department of Agriculture (USDA). The eggs have to go through a process called candling.  First, the eggs are washed.  Then a candling process examines the contents of the egg backlit with a light to look at the conditions of the entire egg.  In modern egg operations, the eggs are now checked by use of sonic sound. It looks for imperfections or blemishes.  If the egg is perfect the machine produces a high pitched sound. If the egg is found to be less than acceptable the machine produces a thud noise. The four types are AA, A , B, and C.  For all grades shells must be intact, but nutritionally the eggs are all the same.

egg-carton-0511-298x232A and AA are almost identical. The difference between the two is that grade A eggs are older than AA eggs and the AA eggs have thicker or firmer egg whites which will hold the yolk in a higher and more round appearance.  The yolk of the Grade A egg may appear to be a little more spread out.  Grade A eggs are the eggs that you see in most stores.  I will  be paying a lot more attention to packaging when I am buying eggs.

Grade B eggs are eggs that have stained, abnormal, or small defects to the outer shell. These eggs are generally used in the food industry as liquid, frozen, or powdered eggs. They can be used to make mayonnaise, cake mix or salad dressings. It will be more difficult to find these eggs in the grocery store in whole egg form.

Grade C eggs may have cracked shells or loose yolks and are typically sold to commercial processors to be used as an additive in other products.

The exterior quality of the egg is actually refers to the shell – it’s appearance and strength. Appearance is important! It’s the first thing you notice.  Cleanliness of the egg is very important because that outer shell defends the egg from any type of contamination. The strength of the egg shell is influenced by the vitamins and minerals in the hens diet – especially vitamin D, calcium phosphorus and manganese.  A strong egg shell will  keep the inside intact until the egg is ready to be used.  Egg shells are also influenced by the age of the hen.  Older hens lay larger eggs with thinner, weaker outer shells.  Just like humans lose bone mass as they age, older hens have a hard time producing calcium rich egg shells.

The shape of the egg is important in its design. The middle of the egg is meant to be weaker so that the chick can peck it through the shell.  The outer ends of the egg must be strong so that the newly laid egg will not crack or break when itdrops from the hen into the nest.  Except for the protection and freshness of the egg, shells have no cooking use.  In the egg industry,the egg shells are often dried, crushed and fed back to hens for the calcium they provide.  They can also be added to soil to sweeten the soil or placed in the planting holes of tomatoes to prevent blossom end rot. Amazingly there is quite an endless list of things that you can do with your eggshells.

Well, I definitely have something to crow about now that I’ve learned so much about the eggs and shells. I think I might check out the whole process that the egg undergoes inside the chicken from start to actually being passed through the hen!

-Sheri

One thought on “Ag 101: Curious Things You Want to Know about Chickens

  1. Pingback: What’s Cookin’? Dark Chocolate Basil Cake | Iowa Agriculture Literacy

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