crack a joke
In ancient China, the proprietors of brothels were called "pimps". Great bustard is a kind of bird. During the mating season, females will mate with many males.
Since the brothel owner is called a "pimp" and a bird, shouldn't the prostitute door she leads also be a bird? So people naturally call them all kinds of birds. But few people seem to be able to match it, so people think of the most common bird-poultry! So there is the saying that prostitutes call chickens.
As for why men call ducks, that's a recent thing. In the early days of reform and opening up, this business was called Cowherd (a term introduced from Hong Kong, Macao and Taiwan). Later, people thought it didn't want to match the common name of prostitutes, so they simply described it as another most common poultry, so there was the saying of duck.
This is the whole story. ......