top of page
Writer's pictureDr. Gaffud

Chicken: Description, Types, Breeds, and Some Common Diseases


A flock of chicken standing on a concrete pedestal

Chickens are one of the most widespread domestic animals. Originating from the wild red junglefowl of Southeast Asia, chickens have been selectively bred for thousands of years for various purposes.


Their primary purpose in production includes providing meat (broilers) and eggs (layers), with some breeds specifically developed for high yield in either category, while dual-purpose breeds offer a balance of both. 


This article explores the following:


What is a Chicken?

A rooster and a hen standing on a pasture land

A chicken (Gallus gallus domesticus) is a domesticated bird that belongs to the Phasianidae family, originating from the wild Red Junglefowl of Southeast Asia. 


“Domestic chickens likely predate archaeological evidence from central Thailand, with southwestern China likely being a key region for their domestication,” according to the 2022 study by Peng, M., Han, J., & Zhang, Y.

Anatomically, chickens possess a beak, comb, wattles, and a feathered body, with a skeletal structure adapted for walking and short flights. They exhibit a variety of plumage colors and patterns, depending on the breed. Chickens are known for their social behavior and a well-defined pecking order within flocks. 


Aside from meat and egg production, chickens also play a role in pest control, waste management, and as a source of feathers and fertilizer.


What are the Different Types of Chicken?

A rooster and four hens ranging on a pasture

Chicken breeds are typically categorized based on their primary use: egg production, meat production, or dual-purpose (both eggs and meat). 


There are hundreds of chicken breeds, each with unique characteristics. Some of them are shown in Table 1. These breeds are developed to adapt to different climates, have varying temperaments, and exhibit diverse physical attributes.


Egg-Type Breeds (Layers)


Egg-type chickens are selectively bred due to their capacity to produce a high quantity of eggs.


“Crossbreeding elite laying chickens, such as Rhode Island Red and White Leghorn, can produce hybrids with favorable egg production traits and egg quality, but heterosis in egg number and clutch size may occur,” according to the 2020 study by Isa, A., Sun, Y., Shi, L., Jiang, L., Li, Y., Fan, J., Wang, P., Ni, A., Huang, Z., Ma, H., Li, D., & Chen, J.

Compared to meat-type breeds, these chicken varieties are typically lighter and are effective at converting feed into high-quality eggs. Some prominent breeds are listed below.


Leghorn: High egg production, adaptability to different environments, and active foraging behavior.

A Leghorn chicken breed standing on a sandy ground with an Italian flag on the top corner
  • Origin: Italy

  • Appearance: White feathers, bright red combs and wattles, yellow legs.

  • Behavior: Active, independent, excellent foragers.

  • Climate Preference: Tolerates heat well, less suited to extreme cold.

  • Production: Approximately 280-320 white eggs per year.

Rhode Island Red: Hardy nature, excellent egg production, and good dual-purpose qualities.

A Rhode Island Red chicken breed standing on a grassland with an American flag on the top corner
  • Origin: United States

  • Appearance: Rich, dark red feathers, sturdy build.

  • Behavior: Hardy, adaptable, relatively calm.

  • Climate Preference: Thrives in both hot and cold climates.

  • Production: Around 250-300 brown eggs per year.

Sussex: Friendly nature, good foraging ability, and decent meat quality.

A Sussex chicken breed foraging on a pasture with an English flag on the top corner
  • Origin: England

  • Appearance: White or light feathers with speckled patterns, red combs.

  • Behavior: Docile, good foragers, friendly.

  • Climate Preference: Prefers cooler climates.

  • Production: About 250-280 brown eggs per year.


Australorp: High egg production, calm temperament, and good adaptability to different climates.

An Australorp chicken breed foraging on a pasture with an Australian flag on the top corner
  • Origin: Australia

  • Appearance: Black feathers with a greenish sheen, red combs.

  • Behavior: Docile, easy to handle, good foragers.

  • Climate Preference: Tolerates cold weather well.

  • Production: Around 250-300 brown eggs per year.


Ancona: Active foragers, good adaptability, and excellent egg production

A Ancona chicken breed standing on a pasture with an Italian flag on the top corner
  • Origin: Italy

  • Appearance: Black feathers with white tips, red combs, yellow legs.

  • Behavior: Active, hardy, excellent foragers.

  • Climate Preference: Adaptable to both hot and cold climates.

  • Production: Approximately 220-280 white eggs per year.


These breeds are valued for their ability to lay plenty of eggs and their suitability to different climates and temperaments, making them suitable for various farming operations, from small-scale backyard setups to large commercial operations.


Meat-Type Breeds (Broilers)


Meat-type chickens are specifically bred for their fast growth rate and large size, making them ideal for meat production. 


“Rapidly growing meat-type chickens grow up to four times faster than layer strains, but this can lead to undesirable consequences like poor reproductive performance, excessive fatness, and skeletal abnormalities,” according to the 1994 study by Griffin, H., & Goddard, C.

These breeds are known for their robust build and efficiency in converting feed into body mass. Some prominent breeds are listed below.


Cornish Cross: (Cornish x White Rock chickens) Rapid growth, high feed conversion efficiency, and large breast meat yield

A Cornish Cross chicken breed standing on a pasture with an American flag on the top corner
  • Origin: USA

  • Appearance: White feathers, broad breast, muscular build with yellow skin, legs, and feet

  • Behavior: Less active, focus on growth rather than foraging, generally calm and docile

  • Climate Preference: Prefers moderate climates; heat-sensitive

  • Production: Ready for slaughter in 6-8 weeks weighing approximately 5-7 pounds, high meat yield

Jersey Giant: Large size, good meat quality, and dual-purpose use.

A Jersey Giant chicken breed foraging on a pasture with an American flag on the top corner
  • Origin: USA

  • Appearance: Black or white feathers, large size

  • Behavior: Docile, calm, slow-growing

  • Climate Preference: Tolerant of cold climates but need adequate shelter

  • Production: Mature at 16-21 weeks weighing up to 13-15 pounds for males and 10-12 pounds for females, produces large quantities of meat


Bresse Gauloise: High-quality meat with a unique flavor, and good foraging ability.

A Bresse Gauloise chicken breed standing on a grassland with an French flag on the top corner
  • Origin: France

  • Appearance: White feathers with blue legs and red combs (French flag colors)

  • Behavior: Active, excellent foragers

  • Climate Preference: Prefers temperate climates

  • Production: Takes 20 weeks to mature weighing 5-7 pounds, high-quality meat


Orpington: Good meat quality, dual-purpose use, and friendly disposition

An Orpington chicken breed standing on a grassland with an English flag on the top corner
  • Origin: England

  • Appearance: Buff, black, blue, or white feathers; large, rounded build

  • Behavior: Calm, friendly, good foragers

  • Climate Preference: Tolerant of cold weather

  • Production: 18-24 weeks to mature 


Freedom Ranger: Good growth rate, strong foraging ability, robust health, and known for their flavorful meat

A Freedom Ranger chicken breed standing on a grassland with a French flag on the top corner
  • Origin: France

  • Appearance: Red or tri-color feathers, medium to large build

  • Behavior: Active, good foragers, more natural growth rate

  • Climate Preference: Adaptable to various climates but perform best in moderate environments

  • Production: Ready for slaughter in 9-11 weeks weighing 5-6 pounds, balanced meat yield


Chickens bred for their meat quality, such as Cornish Cross, Jersey Giant, Bresse Gauloise, Orpington, and Freedom Ranger, have specific characteristics that make them desirable for meat production.


These breeds have different growth rates, sizes, and abilities to adapt to various climates, providing a variety of choices for producing meat, whether on a small scale or for commercial operations.


Dual-type Breeds


Dual-purpose chickens are versatile poultry breeds that are valued for both their meat and egg production. 


Unlike specialized breeds that are optimized for either high egg laying or superior meat quality, dual-purpose chickens provide a balanced performance in both areas. 


“Dual-purpose cockerels of layer and meat breeds achieve moderate growth rates and high animal welfare, making them an ethical option for egg and meat production,” according to the 2021 study by Baldinger, L., & Bussemas, R. 

These breeds are particularly popular among small-scale farmers and backyard poultry enthusiasts who seek efficiency and sustainability in their flocks. Some prominent breeds are listed below. 


Plymouth Rock: Popular for its reliable egg production and attractive striped feathers

A Plymouth Rock chicken breed standing on a grassland with an American flag on the top corner
  • Origin: United States

  • Appearance: Black and white barred feathers; medium size

  • Behavior: Friendly and easy to handle; good foragers

  • Climate Preference: Adaptable to various climates

  • Production: Produces 200-280 brown eggs per year and offers good meat quality

Wyandotte: Recognized for its beautiful plumage and dual-purpose use

A Wyandotte chicken breed standing on a pasture with an American flag on the top corner
  • Origin: United States

  • Appearance: Various colors including silver-laced and gold-laced; rounded build

  • Behavior: Calm and friendly; good foragers

  • Climate Preference: Tolerant of cold weather

  • Production: Produces 200-240 brown eggs per year and good-quality meat

Sussex: Known for its excellent egg production and adaptability

A Sussex chicken breed foraging on a pasture with an English flag on the top corner
  • Origin: England

  • Appearance: White or speckled feathers, sturdy build

  • Behavior: Friendly, active, and good foragers

  • Climate Preference: Adaptable to various climates

  • Production: Produces 250-280 brown eggs per year and provides good-quality meat

Orpington: Versatile breed known for its large size and gentle nature

An Orpington chicken breed standing on a pasture with an English flag on the top corner
  • Origin: England

  • Appearance: Buff, black, blue, or white; large build

  • Behavior: Calm, friendly, and easy to handle

  • Climate Preference: Adaptable to various climates, particularly cold

  • Production: Produces 200-280 brown eggs per year and good-quality meat

Australorp: Known for its high egg production and docile temperament

An Australorp chicken breed foraging on a pasture with an Australian flag on the top corner
  • Origin: Australia

  • Appearance: Black feathers with a greenish sheen, and red combs

  • Behavior: Calm, friendly, and good foragers

  • Climate Preference: Tolerant of cold weather

  • Production: Produces 250-300 brown eggs per year and provides good-quality meat


These hens not only help with various farming activities but also provide the benefit of yielding a consistent stream of eggs and meat all year round.


What are the Different Scales of Chicken Production?

A flock of chicken confined in a coop

Raising chickens serve various purposes, from providing sustenance for a single family to generating substantial profits through large-scale commercial operations. 


The scale of chicken production is typically classified into three main categories: subsistence farming, hobby farming, and commercial farming. 


Each of these scales of production caters to different needs and goals, requiring varying levels of investment, infrastructure, and management practices.


Subsistence Farming


In subsistence agriculture, chickens are raised for the primary purpose of providing both eggs and meat for the family's daily consumption. 


This small-scale production method involves managing modest flocks with minimal investment in infrastructure. Generally, dual-purpose breeds such as Plymouth Rock and Sussex are preferred for subsistence farming as they offer a good balance of egg and meat production. 


These farming practices are typically low-tech, relying on natural foraging and uncomplicated coops. The main objective is self-sufficiency, and any surplus eggs or meat are sold locally to generate a modest income.


Hobby Farming


Hobby farming, also referred to as small-scale or backyard poultry farming, is the practice of raising chickens for personal pleasure and additional income. 


These operations typically consist of flocks larger than subsistence farms but smaller than commercial ones, usually ranging from a few dozen to a couple of hundred birds. 


Hobby farmers often select a variety of chicken breeds to meet their specific needs, with a focus on egg-laying breeds such as Leghorns or meat breeds like Orpingtons. 


The investment in infrastructure is moderate, including secure coops, feeding systems, and sometimes automated egg collection. The eggs and meat produced are commonly sold at local farmers' markets or directly to consumers, providing an extra source of income for the farmers.


Commercial Farming


Large-scale commercial farming is characterized by a strong focus on profitability and substantial investment in infrastructure and technology. 


These operations accommodate thousands to millions of birds, utilizing sophisticated systems for feeding, watering, and egg collection. 


Common breeds used for meat production include Cornish Cross, while high-yield egg-layers like the White Leghorn are also popular. 


Commercial poultry farms adhere to strict biosecurity measures to prevent disease outbreaks and ensure high production efficiency. The primary objective is to produce a large quantity of eggs or meat for the market, necessitating significant capital investment in equipment, housing, and labor.


Factors to Consider when Raising Chickens


  • Housing: Provide secure, well-ventilated coops with adequate space.

  • Nutrition: Balanced diet with appropriate feed for age and purpose (egg-laying, meat production).

  • Health Management: Regular health checks, vaccinations, and parasite control.

  • Breeds Selection: Choose breeds suited to climate, purpose, and management style.

  • Legal Requirements: Check local regulations regarding chicken keeping.

  • Predator Protection: Secure enclosures to protect from predators.


5 Common Chicken Health Problems


A veterinarian in a complete gear for flock check-up

Raising chickens is a rewarding endeavor, but it comes with its challenges, particularly in managing the flock's health. 


Understanding common health problems and their management is crucial for maintaining a healthy and productive flock. 


Five chicken health issues are discussed below.


Marek's Disease

  • Cause: highly contagious herpesvirus

  • Transmission: feather dander, dust, and direct contact with infected birds or contaminated environments

  • Clinical Signs: paralysis of the legs, wings, and neck, weight loss, irregular pupil size, and tumors in various organs

  • Treatment: no effective treatment once birds are infected

  • Prevention: Vaccination (at one day old) and strict biosecurity practices 


Coccidiosis

  • Cause: protozoan parasites from the genus Eimeria, infecting the intestinal tract.

  • Transmission: ingestion of sporulated oocysts found in contaminated feed, water, or litter

  • Clinical Signs: diarrhea (often bloody), weight loss, reduced growth rates, droopiness, and a decreased appetite

  • Treatment: Anticoccidial medications through feed or water 

  • Prevention: vaccination, clean living conditions, regular cleaning and disinfecting of the coop, providing fresh water, and rotating pastures to reduce the build-up of oocysts. 


Avian Influenza

  • Cause: avian influenza viruses, with the H5 and H7 subtypes being particularly pathogenic.

  • Transmission: direct contact with infected birds, contaminated equipment, and environmental exposure

  • Clinical Signs: respiratory distress, coughing, sneezing, decreased egg production, swelling of the head, and sudden death

  • Treatment: No specific treatment for AI; culling of infected flocks to prevent the spread of the disease

  • Prevention: Biosecurity measures, monitoring, and testing for AI


Fowl Pox

  • Cause: avipoxvirus

  • Transmission: direct contact with infected birds, contaminated environments, and mosquito bites

  • Clinical Signs: two forms: cutaneous (dry pox) characterized by wart-like lesions on the skin, and diphtheritic (wet pox) affecting the mucous membranes, causing lesions in the mouth and respiratory tract

  • Treatment: no specific treatment; supportive care and secondary infection management 

  • Prevention: vaccination, mosquito control 


Egg Binding

  • Cause: egg gets stuck in a hen's reproductive tract

  • Transmission: not contagious but results from factors like poor nutrition, obesity, lack of exercise, and laying large eggs

  • Clinical Signs: hen straining, lethargy, reduced appetite, and sitting for extended periods.

  • Treatment: immediate veterinary intervention, warm baths, gentle massage, and calcium supplementation to assist in expelling the egg

  • Prevention: a balanced diet rich in calcium, overweight prevention, opportunities for exercise, avoid breeding for excessively large eggs.


Probiotics can significantly reduce reproductive tract pathologies and increase hen health and performance in free-range laying hens, benefiting hen welfare and egg producers,” according to the 2013 study by Shini, S., Shini, A., & Blackall, P.


Chicken Breeds


There are 71 breeds of chicken according to OSU. Table 1 shows the list of these breeds.

Table 1. Chicken Breeds
  1. AC Chickens

  2. Ameraucana Chickens

  3. Ancona Chickens

  4. Andalusian Chickens

  5. Appenzell Bearded Hen Chickens

  6. Appenzell Pointed Hood Hen Chickens

  7. Araucana Chickens

  8. Aseel Chickens

  9. Australorp Chickens

  10. Baheij Chickens

  11. Bandara Chickens

  12. Barnevelders Chickens

  13. Brahma Chickens

  14. Buckeye Chickens

  15. Buttercup Chickens

  16. Campine Chickens

  17. Catalana Chickens

  18. Chantecler Chickens

  19. Cochin Chickens

  20. Cornish Chickens

  21. Crevecoeur Chickens

  22. Cubalaya Chickens

  23. Delaware Chickens

  24. Dominiques Chickens

  25. Dorking Chickens

  26. Dutch Bantam Chickens

  27. Faverolles Chickens

  28. Friesian Chickens

  29. Frizzle Chickens

  30. Gimmizah Chickens

  31. Golden Montazah Chickens

  32. Hamburg Chickens

  33. Holland Chickens

  34. Houdan Chickens

  35. Java Chickens


  1. Jersey Giant Chickens

  2. La Fleche Chickens

  3. Lakenvelder Chickens

  4. Lamona Chickens

  5. Langshan Chickens

  6. Legbar Chickens

  7. Leghorn Chickens

  8. Marans Chickens

  9. Malay Chickens

  10. Matrouh Chickens

  11. Minorca Chickens

  12. Modern Game Chickens

  13. Naked Neck Chickens (Turken)

  14. Nankin Chickens

  15. New Hampshire Red Chickens

  16. Old English Game Chickens

  17. Orpington Chickens

  18. Plymouth Rock Chickens

  19. Polish Chickens

  20. Red Cap Chickens

  21. Rhode Island Red Chickens

  22. Russian Orloff Chickens

  23. Sasso Chickens

  24. Sebright Chickens

  25. Shamo Chickens

  26. Silkie Bantam Chickens

  27. Silver Montazah Chickens

  28. Styrian Chickens

  29. Sultan Chickens

  30. Sumatra Chickens

  31. Sussex Chickens

  32. Swiss Hen Chickens (Schweizerhuhn)

  33. Welsummer Chickens

  34. White-Faced Black Spanish Chickens

  35. Wyandotte Chickens

  36. Yokohama Chickens

References: 

Comments


bottom of page