Kokoš je u kokošinjcu, a pijetao je vani.

In this sentence, a links two clauses but also sets up a contrast:

• Kokoš je u kokošinjcu = the hen is in the henhouse
• a pijetao je vani = while/but the rooster is outside

So a often means something like:

• and, when comparing two things
• while
• whereas
• sometimes but, if there is a mild contrast

If you used i, it would sound more like simple addition: and. Here, a is better because the two animals are in different places.

Because Croatian normally uses the verb biti = to be in each clause:

• Kokoš je u kokošinjcu
• pijetao je vani

English can sometimes avoid repeating is, but Croatian usually keeps it. Repeating je makes the structure clear and natural.

You may sometimes hear shortened or more elliptical speech, but for a learner, repeating je in both parts is the safest and most standard pattern.

Because after u, when you mean location (in, inside), Croatian uses the locative case.

So:

• kokošinjac = nominative/basic form
• u kokošinjcu = in the henhouse

This is an important pattern:

• u + locative = location
• u + accusative = movement into something

Compare:

• Kokoš je u kokošinjcu. = The hen is in the henhouse.
• Kokoš ide u kokošinjac. = The hen is going into the henhouse.

Kokošinjcu is locative singular.

Here is the basic breakdown:

• kokoš = nominative singular
• je = is
• u kokošinjcu = preposition u
  • locative singular
• pijetao = nominative singular
• vani = adverb

So the subject nouns kokoš and pijetao are in the nominative, while kokošinjcu changes because it comes after u in a location meaning.

Because vani is an adverb, not a noun phrase.

It simply means:

• outside
• outdoors

So Croatian says:

• Pijetao je vani. = The rooster is outside.

You do not need a preposition before vani.

This is similar to English adverbs like here, there, or outside.

Yes. Kokoš is a feminine noun, even though it ends in a consonant.

This is something English speakers often notice because many feminine Croatian nouns do end in -a, but not all of them do.

A number of feminine nouns end in a consonant, especially words like:

• kokoš = hen
• noć = night
• stvar = thing

So you cannot rely only on the ending. You have to learn the noun’s gender along with the word.

Because they are related.

• kokoš = hen
• kokošinjac = henhouse / chicken coop

The word kokošinjac is built from kokoš and refers to the place where hens/chickens are kept.

This is common in Croatian: a basic noun can be used to form another noun connected to it.

So seeing the similarity is helpful, not confusing: it is a clue to the meaning.

Correct: standard Croatian does not have articles like English the and a/an.

So:

• Kokoš can mean a hen or the hen
• pijetao can mean a rooster or the rooster

The exact meaning depends on context.

This is very normal in Croatian, so when translating into English, you add a or the based on the situation.

Yes. Croatian word order is more flexible than English because case endings help show the grammatical roles.

The given sentence is a natural, neutral order:

• Kokoš je u kokošinjcu, a pijetao je vani.

But other orders are possible for emphasis, for example:

• U kokošinjcu je kokoš, a pijetao je vani.
• Pijetao je vani, a kokoš je u kokošinjcu.

These do not all feel identical in emphasis, but they are grammatically possible.

For beginners, the original version is the best one to learn first.

Because a connects two full clauses:

• Kokoš je u kokošinjcu
• pijetao je vani

In Croatian, when a joins two independent clauses like this, a comma is normally used.

So the punctuation here is standard and expected.

Yes, depending on context.

Most specifically:

• kokoš = hen
• pijetao = rooster

But in everyday use, kokoš can sometimes also refer more generally to a chicken, especially when the sex is not the main point.

In this sentence, because pijetao is also mentioned, kokoš is most naturally understood as hen, the female bird.

They do different jobs:

• u is a preposition meaning in/inside or into, depending on case
• vani is an adverb meaning outside/outdoors

So:

• u kokošinjcu = in the henhouse
• vani = outside

English speakers sometimes expect a matching structure like in the henhouse / outside the henhouse, but Croatian does not need to say the second part explicitly if the meaning is already clear.