Hun lufter hunden hver morgen.

Because hunden is the definite form: the dog.

In Norwegian, the definite article is usually attached to the end of the noun instead of being a separate word like English the.

• en hund = a dog
• hunden = the dog

So in this sentence, hunden refers to a specific dog, probably one already known from the context.

The base form is å lufte.

Here, lufter is the present tense form:

• å lufte = to air / to take out
• lufter = airs / takes out

With a dog, å lufte hunden usually means to take the dog out, often for fresh air, exercise, or a walk.

No. In Norwegian, verbs do not change according to the subject the way they do in English.

English:

• I walk
• she walks

Norwegian:

• jeg lufter
• du lufter
• hun lufter
• vi lufter

So lufter stays the same no matter who does the action.

Yes, literally it comes from the idea of giving something air or fresh air. But in normal usage, with a dog, it means something like:

• take the dog out
• walk the dog
• let the dog get some fresh air

So the literal idea is there, but the natural meaning is broader than just air the dog.

Hver morgen is the normal way to say every morning.

• hver = each / every
• morgen = morning

So:

• hver morgen = every morning

Alle morgener would sound much less natural here. It means something more like all mornings, which is not the usual expression for a repeated daily habit.

Because after hver, Norwegian normally uses the noun without an article.

So you say:

• hver dag = every day
• hver uke = every week
• hver morgen = every morning

Not:

• hver en morgen in normal standard usage here

This is similar to English, where we also say every morning, not every a morning.

This sentence uses the very common Norwegian main-clause order:

Subject + verb + object + time expression

So:

• Hun = subject
• lufter = verb
• hunden = object
• hver morgen = time expression

You can move the time expression to the front, but then Norwegian follows the V2 rule: the verb must still stay in second position.

For example:

• Hver morgen lufter hun hunden.

That is also correct.

Yes, in many contexts that is the most natural English translation.

But å lufte hunden is a little broader than just walk the dog. It can mean taking the dog out in general, not necessarily for a long walk. Depending on context, it could be:

• taking the dog out briefly
• letting it get fresh air
• taking it for a walk

So walks the dog every morning is often a good translation, but not always the only possible one.

Because hun is the subject form of she.

• hun = she
• henne = her

In this sentence, she is doing the action, so Norwegian uses hun.

Compare:

• Hun lufter hunden. = She takes the dog out.
• Jeg ser henne. = I see her.

In Bokmål, hund is usually a common gender noun:

• en hund = a dog
• hunden = the dog

So yes, gender matters because it affects the article and the definite ending.

However, for many common-gender nouns in Bokmål, this becomes quite natural once you learn the pattern:

• en bil → bilen
• en katt → katten
• en hund → hunden

You would use the past tense of å lufte, which is luftet:

• Hun luftet hunden hver morgen.

That means She took the dog out every morning or She walked the dog every morning.

A useful mini-pattern:

• infinitive: å lufte
• present: lufter
• past: luftet
• past participle: luftet

Yes, it is completely natural.

Hun lufter hunden hver morgen is a normal, idiomatic sentence. A Norwegian speaker might also say something more specific depending on what they mean, for example:

• Hun går tur med hunden hver morgen. = She goes for a walk with the dog every morning.
• Hun tar med hunden ut hver morgen. = She takes the dog out every morning.

But your original sentence is very standard and natural.