In Romanian, do words with the definite article, such as "puii" (the chickens) and "curcanii" (the turkeys) refer to the whole species, or only to specific groups of individuals. In English, when we say "chickens are birds," we mean the whole class / species of chickens, not just some specific chickens. Is this rendered in Romanian by "puii sunt păsări"?
Both. Context will make it clear if it's a general statement (yes, Puii sunt păsări. = Chickens are birds. --- meaning all of them) or something specific.
In Romanian, the subject has to have an article; usually, it's the definite article. The only exception that comes to mind is when you say something about the word itself, for example, "Pui" este un cuvânt scurt. = "Chickens" is a short word., but this is meta-language already. The complete phrase is Cuvântul "pui" este un cuvânt scurt., which has the definite article on the subject noun.
Not sure if I understand your question. We use one article or the other depending on what we want to communicate, not on the number of the noun.
Coto.i wrote ”In Romanian, the subject has to have an article; usually, it's the definite article.”
Now, in my impression, for singular subjects the indefinite article seems quite common and certainly not exceptional:
- O femeie traversează piața.
- Un băiat coboră din autobuz.
Of course it depends on the meaning which article is used.
In contrast, in the plural you either have to use the definite article or something like ”niște” or ”câțiva”:
- Femeile traversează piața.
- Băieții coboră din autobuz.
- Niște femei traversează piața.
- Câțiva băieți coboră din autobuz.
The latter seems less common, so here I agree that ”usually it's the definite article.”
Am I getting something wrong? (Sorry for grammar or lexical errors.)
So you ask why I said "usually"? That's just my subjective impression that statistically, we use specified nouns (no matter they are singular or plural) more than unspecified nouns. Hence the predominance of the definite article.
But all articles are common. Or other way said they are certainly not uncommon or exceptional.
As a difference between the languages, it's worth mentioning that there are cases in which the subject noun does not have an article in English, but it does have in Romanian. From https://learnenglish.britishcouncil.org/beginner-grammar/articles-1:
When we talk about things in general we usually use a plural noun or an uncountable noun with no article.
- Birds eat worms. NOT The birds eat the worms. --> Păsările mănâncă viermi. (NOT Păsări...)
- Water flows downhill. --> Apa curge la vale. (NOT Apă...)
- Kangaroos live in Australia. --> Cangurii trăiesc în Australia. (NOT Canguri...)
In the above examples in Romanian the definite article is used.