Theory of Origin of Domestic Chicken

There are two theory regarding in origin of chicken. These are -

1)   Monophyletic Theory.

      2) Polyphyletic Theory.

Monophyletic Theory: This theory is based on the observation of Darwin. He (1896) gave detail consideration that the red jungle fowl (Gallus gallus) is the only ancestor of domestic fowl. Most scientists agreed with him. But this question is still not fully resolved.

Darwin’s Observation:

1.    Fertility rate high in case of Recd jungle fowl.

2.    Roosting in the trees. Flying characteristics like domestic fowl.

3.    Plumage color very strong like Red jungle fowl & also Plumage pattern.

4.    Female Red jungle fowl plumage pattern similar to female white Leghorn.

Polyphyletic Theory: The polyphyletic theory attributes the origin of domestic fowl to different wild fowl species (either existed or extinct) including Gallus gallus.

Agreement/criticism in favor of polyphyletic theory:

a. Voice: The voice of modern domestic fowl is different from Gallus gallus

b.  Size: The modern breeds like Jersey Black Giants are much bigger than Gallus gallus and other existing wild fowl.

c.  Diversification & Differentiation: Are more in domestic chicken than wild fowl including Gallus gallus.

d.  Wattles: Unlike wild fowl the wattle are either absent or reduced in Aseel and Chantecler.

e.   Plumage: The dominant white silver plumage is absent in Gallus gallus but present in G.sonnerati and G.domesticus

f.   Eggshell color: The modern breed lay white and brown shelled egg but Gallus gallus lay buff colored shelled egg.

g.   Toe: Unlike wild chicken Dorkings and Haudon breeds got 5 toes.

h. Temperament: The physical temperament of Asiatic breeds is different from existing wild fowl. They are heavier, slow in movement and less capable to fly.

i.     Comb: Pea comb and Rose comb are absent in wild birds.

j.  Sickle Feather: Unlike wild fowl the sickle feather of Japanese breed Yokohama may be as long as 4.8 meters.

k. Shank Feather: Breeds of Asiatic class has feathered shank unlike Gallus gallus.

l.   Egg production: Wild fowl lay only few eggs while modern domestic fowl may lay above 300 eggs per year.

 
After the above discussion and observation most of the scientists express heir opinion in Polyphyletic Theory for the origin of modern domestic fowl. According to this theory the scientific name of modern domestic fowl should be Gallus domesticus.