Egg-cited about Eggs!
By: Dr. Kimberly Vonnahme
I am egg-cited to tell you all about chickens today!! I am sure this will be an egg-cellent read for you. Life on the farm allows us to see things on the sunny-side (up) of life…. and I am here to share eggs-actly what you need to know about our feathered friends at Harvest Hope Farm: the chickens!!!
The domestic chicken (Gallus gallus domesticus) has been primarily used by humans as a source of food: both meat and eggs. Some people do have chickens as pets (Fun Fact #1: my grandmother’s first pet was a chicken), but chickens were domesticated to help keep us nourished. Male chickens are termed roosters (Fun Fact #2: Males less than a year of age are called cockerels). Female chickens are called hens (Fun Fact #3: Younger females are called pullets). Baby chickens are called chicks.
Chickens are omnivores: they eat both vegetation and meat. Their favorite source of meat are bugs, but it has been documented that a chicken can take down small snakes and young mice. Depending on the breed of chicken, chickens can live for 5 to 10 years!
There are over 100 breeds of chickens! Chickens have been selected over the centuries for different colors and other traits that humans wanted to showcase. (Fun Fact #4: Harvest Hope Farm is home to 4 different breeds of chickens: Jersey Giants, Americana, Delaware, and Rhode Island Reds!). Today, there are breeds of chickens that are known as broiler breeds (i.e. for their meat production) and layer breeds (i.e. for their ability to lay eggs).
The broiler breeds encompass the breeds that have been selected for their ability to grow well and put on a lot of muscle, particularly the breast muscle. Broiler chickens are very efficient in their growth—they can gain ~1.7 pounds for each pound of feed they consume (i.e. Feed Conversion Ratio; FCR). To put this in perspective, the FCR is 6.8 in cattle, 6.3 for sheep, 2.9 in swine, and 1.1 for fish. Depending upon the breed of broiler, it can take 6 to 9 weeks to reach the appropriate butcher weight (Fun Fact #5: Did you know that 92 lbs of chicken is consumed by each person in the US each year?). Of course, to propagate more broilers for meat consumption, there are hens that lay eggs—but only for hatching new chicks for the broiler industry to provide safe, healthy meat for our families. (Fun Fact #6: A chicken egg takes 21 days to hatch).
On the flip side, we have the layer breeds. As their name implies, these chickens have been selected for their ability to lay eggs (Fun fact #7: A layer hen can lay one egg every 24-26 hours). The egg laying process is controlled by light hours, so hens lay more eggs in the summer than in the winter. In general, after the yolk is ovulated (i.e. the yolk is released from the follicle on the hen’s ovary), it spends about 30 minutes in the first part of the oviduct (Fun Fact #8: Hens do not need a rooster around to lay eggs). Then it takes about 3 hours for the egg white to form around the yolk and it grows. The shell membrane is then added to form the egg shape, which takes an hour. The longest time the egg spends in the chicken is when the hard-shell layer is added. This takes ~20 hours. Finally, the egg will be laid as it passes through the remainder of the hen’s reproductive tract. As it passes, the cuticle is laid on the egg, a layer that protects the egg from bacteria. Thirty minutes after the egg is laid, the ovary of the chicken will release another yolk, and the process begins again. This process will repeat itself about 10 times, then the hen will take a day off before the cycle begins again. (Fun Fact # 9: This group of eggs in the 10 day window is called a clutch).
In breeds that lay colored eggs, pigments, called porphyrins, are secreted from cells within the uterus (where the hard shell comes from) to add color to the egg shells during the last 5 hours of shell formation. Hens that lay white eggs do not produce any pigments during shell formation. (Fun Fact #:10 You can tell the color of the egg shell by the color of the hen’s ear lobe: white lobes will lay white eggs, red lobes will lay brown/green eggs).
Layer hens need ~2 lbs of feed to produce 1 pound of eggs. Layer hens in commercial layer farms lay up to 330 eggs a year! (Fun Fact #11: In 2019, it was estimated that the average person in the United States consumed 289.5 eggs!).
Chickens are one of the highlights at Harvest Hope Farm! (Fun Fact #12: Chickens were the first livestock at Harvest Hope Farms!). My kids, along with our Farm Campers, love feeding the chickens and searching for eggs. When the broilers are at the Farm, we all get to witness the amazing growth potential these birds have! I know that there are many more egg-citing adventures for our Farm Campers in the next weeks, and if you interested in learning more about how your kids can participate in Farm Camp next year, please inquire!
Thanks for reading Kim’s Korner, where you always get the Right Angle on Animal Science! Did you eggs-amine the dozen Fun Facts within the article?
--Dr. Kimberly Vonnahme is an animal scientist that loves sharing her passion for agriculture. She enjoys her eggs over-easy with a side of crispy bacon and strong cup of coffee. When she is not researching animal health, she loves hanging out with her kids and husband, spending time at Harvest Hope Farm, and learning more about the wonderful creations that God has given us.