Bibi alisema punje hizo ni nzuri kwa vifaranga.

Alisema is made of:

• a- = he/she
• -li- = past tense
• -sema = say

So alisema means he/she said.

Because the subject is already built into the verb, Swahili does not need a separate word like she before said.

Swahili often leaves out kwamba (that) after verbs like say.

So both of these are natural:

• Bibi alisema punje hizo ni nzuri kwa vifaranga.
• Bibi alisema kwamba punje hizo ni nzuri kwa vifaranga.

The version without kwamba is very common and sounds normal.

Because many Swahili nouns in class 9/10 have the same form in singular and plural.

So:

• punje hiyo = that grain/seed
• punje hizo = those grains/seeds

The noun itself stays punje; the words agreeing with it, like hiyo/hizo, show whether it is singular or plural.

Hizo is a demonstrative meaning those, and it agrees with the noun class of punje here.

Since punje is plural in this sentence, the demonstrative must also be plural:

• singular: hiyo
• plural: hizo

So punje hizo means those grains/seeds.

Ni is the basic Swahili copula, the word that means is / are in sentences like this.

So:

• ni nzuri = is good / are good

Swahili uses the same ni for both singular and plural here. The noun tells you whether English should be is or are.

Nzuri means good.

It agrees with punje, which belongs to the 9/10 noun classes. With this class, the adjective form is nzuri. Conveniently, it looks the same in both singular and plural:

• punje hiyo ni nzuri = that grain is good
• punje hizo ni nzuri = those grains are good

So even though English changes is/are, the adjective nzuri stays the same.

Here kwa means something like for in the sense of suitable for / good for.

So nzuri kwa vifaranga means good for chicks.

This is a very common use of kwa:

• nzuri kwa watoto = good for children
• mbaya kwa afya = bad for health

The singular is kifaranga.

This is a ki-/vi- noun pair:

• kifaranga = one chick
• vifaranga = chicks

So vi- is the normal plural marker for this noun class.

Swahili does not have articles like English a/an/the.

Whether something is definite or indefinite usually comes from:

• context
• a demonstrative like hiyo/hizo
• other parts of the sentence

So punje hizo already clearly points to those grains/seeds, and no separate word like the is needed.

The given word order is very normal:

• Bibi alisema = main clause
• punje hizo ni nzuri kwa vifaranga = what she said

You can also say:

• Bibi alisema kwamba punje hizo ni nzuri kwa vifaranga.

That is also correct and maybe a little more explicit because it includes kwamba. But the original version is completely natural.