What is a sport?

[wegotchickens]

The term 'sport' is also used to describe any mutations that show up and are unrelated to either parent. Like an albino buffalo would be a sport.

 

[holdinggold]

In Netherland Dwarf & some other rabbit breeds, when you are breeding for Blue-Eyed Whites, you will get a black & white rabbit, usually marked like a Dutch, that has blue eyes. That's called a sport as well.

 

[wclawrence]

This hen is a "blue splash sport".
She is out of a Black Sumatra hen and a normal colored Denizli rooster, neither of them carry blue or have had blue in the family for a few generations I know for a fact.

The term for her is "blue splash sport" because (1) the color is blue (2) she has two copies and (3) it is a conundrum that she came this color, being that she has no blue parents.

Normally for a bird to have 2 copies of blue, both parents have to have at least one copy.

 

[Jashdon]

The term sport is used for plants as well. It is usually a genetic mutation that occurs on a branch that is then cut off and propogated to form a new form of the parent plant.

 

[Blisschick]

Basically, I've always understood the word "sport" (as related to animals and plants) as a spontaneous, unrelated genetic mutation that has appeared in a population or as an offshoot. For whatever reason, the gene has appeared and has nothing to do with the parent(s) genetic makeup, meaning there was no way they could have contributed to the new quality the offspring has.

As far as chickens go, I know the splash version of fawn in OEGB is called a "sport", but since it's an established color, I don't know why it's called this. I do know that blue Jersey Giants are the result of a spotted sport that popped up in Gold Miller's white flock way back, so no outside breed was used to bring blue into the blue breed.