kainusi ga siiku ni tuite kiku.

が marks the grammatical subject.

Here, 飼い主が means the owner is the one who asks.
So 飼い主 is the person doing the action 聞く.

In a simple sentence like this:

• 飼い主が = the owner
• 聞く = asks

So が is showing who performs the action.

について means about, concerning, or regarding.

So:

• 飼育について = about animal care / about raising animals / regarding breeding or keeping animals

Grammatically, について attaches to a noun.
Here, it attaches to 飼育.

You can think of the pattern as:

• noun + について + verb
• Xについて聞く = to ask about X

Examples:

• 日本について話す = talk about Japan
• 仕事について考える = think about work
• 飼育について聞く = ask about animal care

In について, the に is part of the set expression について. It is not functioning separately in the way it does in many other sentences.

So it is best to learn について as one grammar pattern meaning:

• about
• regarding
• concerning

In other words, do not split it up and try to translate each piece literally in this sentence.
Just treat 飼育について as about animal care.

飼育 is a noun, and it can also act as a suru-noun.

That means:

• 飼育 = breeding, raising, keeping, animal husbandry
• 飼育する = to raise / to breed / to keep animals

In your sentence, 飼育 is being used as a noun:

• 飼育について = about animal care / about raising animals

This is different from 飼う, which is a plain verb meaning to keep or to raise an animal.

Compare:

• 犬を飼う = keep a dog
• 飼育について聞く = ask about animal care / ask about how to raise an animal

The dictionary form 聞く is the plain non-past form.

It can mean:

• present habitual: asks
• future: will ask

In isolated example sentences, Japanese often uses dictionary form because it is the basic form used in grammar explanations and vocabulary examples.

So this sentence is not necessarily talking about the past. It simply presents the action in a neutral way.

If you wanted other forms:

• 聞きます = asks / will ask (polite)
• 聞いた = asked
• 聞きました = asked (polite)

聞く can mean both hear/listen and ask, depending on context.

In this sentence, it means ask because of the pattern:

• Xについて聞く = ask about X

So 飼育について聞く naturally means ask about animal care, not hear about animal care.

This is very common in Japanese: one verb can cover meanings that English separates into different verbs, and context tells you which one is meant.

Because 飼育 is not the direct object of 聞く here.

The sentence is built like this:

• 飼い主が = the owner
• 飼育について = about animal care
• 聞く = asks

The phrase Xについて聞く is the standard way to say ask about X.

If you used を, it would suggest a different structure, and 飼育を聞く would not sound natural in normal Japanese.

So the correct pattern is:

• Xについて聞く

not

• Xを聞く for the meaning ask about X

Usually, 飼い主 means the owner/caretaker of an animal, often a pet owner.

It is made from:

• 飼い from 飼う = to keep or raise an animal
• 主 = owner, master

So 飼い主 is the person who keeps the animal.

Depending on context, it can refer to:

• a pet owner
• the owner of a dog or cat
• sometimes more broadly, the keeper of an animal

In everyday usage, many learners first encounter it with pets.

Yes, it is grammatical, but the nuance is a little formal or technical.

飼育 is a somewhat formal word. It is often used for:

• animal care
• breeding
• keeping animals
• husbandry
• zoo or facility contexts
• instructions about how to raise an animal

In casual conversation, depending on the situation, people might also say things like:

• 飼い方について聞く = ask about how to raise it
• 世話の仕方について聞く = ask about how to take care of it

So 飼育について聞く is fine, but it may sound a bit more official, educational, or technical than the most casual everyday phrasing.

It is read:

かいぬし が しいく について きく。

Word by word:

• 飼い主 = かいぬし
• が = が
• 飼育 = しいく
• について = について
• 聞く = きく

A learner may notice that 飼育 and 聞く both contain a きく/く sound pattern nearby, but they are different words:

• しいく = animal raising / breeding
• きく = ask / hear / listen

No, normal Japanese writing usually does not use spaces between words.

A natural written version would be:

飼い主が飼育について聞く。

Spaces are often added in teaching materials to help beginners see word boundaries more easily.

So the spaced version is a learning aid, not standard Japanese formatting.