When they get the injections from a rooster's comb, the rooster does have to be killed. They can get rid of a rooster's comb without killing it but it has to be on the first day that it is born.
A rooster's crest is the fleshy, red comb on top of its head. It is used for attracting mates and regulating body temperature. The size and shape of the crest can vary depending on the rooster's breed.
If they have a comb
it is on top of their heads
Red.
It is called a comb.
The prepositional phrase in the sentence is "with the zigzag comb," which provides additional information about the White Leghorn rooster.
A rooster's comb is mainly used for regulation of body heat.
"With the zigzag comb"
The thing on a rooster's head is called a comb.
A Leghorn rooster is a large white bird with a red comb.
"With the zigzag comb"