The question of what two birds make a chicken is an interesting one that touches on genetics, evolution, and animal husbandry. At its core, a chicken is the result of the breeding between a male and female of the same species, specifically red junglefowl. The red junglefowl (Gallus gallus) is a tropical member of the Pheasant family that is thought to be the wild ancestor of the domestic chicken. Selective breeding of this bird over thousands of years has produced the different breeds of chickens we are familiar with today. So in essence, two red junglefowl mating together originally produced what we now know as the domestic chicken.
Origin of Chickens
Chickens were first domesticated around 8,000 years ago in Southeast Asia. Originally kept for cockfighting purposes, over time chickens were selectively bred for traits like egg production, meat yield, and docile behavior. While modern chicken breeds appear quite different from junglefowl, they remain the same species and are still capable of interbreeding. The wild ancestors of chickens, red junglefowl, naturally have a social structure where a dominant male will mate with multiple females, so domestication took advantage of their natural breeding behavior.
Genetics of Chicken Breeding
All chicken breeds are consider the same species, Gallus gallus domesticus. They are able to successfully mate and produce viable, fertile offspring. The different breeds we see today are simply the result of selective breeding emphasizing certain traits. For example, Leghorn chickens were bred for egg laying while Cornish chickens were bred for meat production. All chickens share a common gene pool, and their diversity stems from slight variations in the frequency of alleles and recombination of existing genes into new traits. No new genetic material is introduced in developing new breeds.
Role of Rooster and Hen in Breeding
For a chicken to be produced, you need both a male (rooster) and female (hen). The rooster provides the sperm containing DNA to fertilize the egg from the hen. The fertilized egg divides and incubates over 21 days, resulting in a chicken with genetic material from both parents. While hens lays eggs regularly, a rooster must mate with the hen in a process called treading for the eggs to become fertile and hatch into chicks. Both parents contribute equally to the genetic makeup of their offspring.
Rooster’s Role
| Role | Description |
|---|---|
| Fertilization | Provides sperm to fertilize the hen’s eggs |
| Protection | Guards flock from predators |
| Thermoregulation | Keeps hens warm by spreading out wings |
The rooster provides the male genetic component through fertilization. A virile rooster can mate with 10-12 hens, fertilizing all their eggs. Roosters will also act territorial and aggressive to protect their flock. Finally, roosters help regulate hen’s body temperature, keeping them warm.
Hen’s Role
| Role | Description |
|---|---|
| Egg production | Lays fertilized eggs |
| Incubation | Sits on and incubates fertilized eggs |
| Brooding | Cares for hatched chicks |
The hen provides the female genetic component by laying the eggs that get fertilized. Good egg-laying hens can produce 200-250 eggs per year. The hen will then incubate the eggs for 21 days until chicks hatch. Mother hens will brood and care for the hatched chicks until they mature.
Breeding Chickens Artificially
With the advent of artificial insemination, roosters are no longer essential for breeding chickens. The semen can be manually collected from select males and used to inseminate hens. This allows breeders to be very selective and eliminate the need for live roosters. Artificial insemination ensures the hen’s offspring come from the chosen male’s genetics. However, most family backyard chicken keepers will use a live rooster for natural breeding.
Incubation and Hatching
Once a rooster fertilizes a hen’s eggs successfully, the embryos inside the egg will begin developing. The hen will then take over incubating the eggs, keeping them at the correct warm temperature until hatching. Incubation takes about 21 days before the chicks emerge fully formed from the eggs. The mother hen will have helped the chicks hatch by pecking the shell and making noises. She will then raise them and provide food and warmth.
Incubation Period
| Days | Development Milestone |
|---|---|
| 1-7 | Fertilized blastodyst forms and embryo develops |
| 8-14 | Feathers, beak, claws, and egg tooth form |
| 15-21 | Yolk sac pulled into body cavity, chick hatches |
It takes 21 days for a fertilized egg to incubate and hatch. In the first week the embryo forms from the fertilized cell. Then key features like feathers and the beak develop in the second week. Finally in the last week before hatching the chick pulls its yolk sac into its body and emerges fully formed.
Conclusion
In summary, two red junglefowl, specifically a male rooster and female hen, breeding together produce what we know as domestic chickens. Selective breeding over thousands of years has given rise to the different chicken breeds, but they all originate from the red junglefowl. The rooster provides the sperm to fertilize the hen’s eggs, which then incubate for 21 days before hatching. So while they may look very different today, all chickens can trace their ancestry back to the mating of two red junglefowls, making them the original parents of the chicken.
