Be aware that "des" is simply the plural of "un/une". There is no real counterpart for this in English. Some people have the idea that it must be translated as "some" (through unintentional Duolingo presentations), but this "some" is almost always ignored in English. I.e.,
- un livre, des livres = a book, books (not "some books")
- une pomme, des pommes = an apple, apples (not "some apples")
Although it is used as an auxiliary and in a number of expressions where it kind of loses its meaning, "avoir" still means "posséder". The quality of your French will (eventually) be judged by how cleverly you use synonyms, to avoid "flat" speech and boring repetitions.
Sorry for the long speech... "vous pouvez posséder des canards" is very good French.