I want to know the answer to the following question:
Where ducks ever used as a type of commerence in the world?
All the background I'm provided with is that "Despite this, ducks did not appear in agricultural texts in Western Europe until about 810 AD, when they began to be mentioned alongside geese, chickens, and peafowl as being used for rental payments made by tenants to landowners.". Is that enough to answer the question?