Sure. Had the Normans been the only outside group coming to the British islands after Rome left it would be fine to call them Norsemen, Germanics or even just continentals, but due to the long sequence of invasions it is very reasonable to use and expect the most specific terms. The word "poultry" certainly did not come on a boat before 1066, and only on a very specific subset of the boats that came that year.
Normans descended from the Norse (hence the name) but the Normans adopted the French language which is the point here.
Re:Why “children,” not “childs”? (2016)
by toasterlovin on Monday May 28, 2018 @04:38PM
(#17174700)
Although, interestingly, they spoke a dialect of French that is different from, for example, Parisian French. And you can tell when a word was borrowed into English from French based on whether it starts with consonant sounds that are from the Norman dialect vs. the Parisian dialect. As an example (IIRC), William is a Norman name, whereas Guillaume is the Parisian version of the same name.
Side note: if that kind of stuff is interesting to you, I can highly recommend The History of English podcast.
They tried to conquer England for the best part of a millennium, failed, conquered parts of France and Italy instead - by war and diplomacy - and then conquered England.