این گوشت از آن یکی گران تر است، اما مرغ ارزان تر است.

Persian usually makes the comparative by adding ـتر to an adjective:

• گران = expensive

• گران‌تر = more expensive

• ارزان = cheap
• ارزان‌تر = cheaper

So:

• این گوشت ... گران‌تر است = this meat is more expensive
• مرغ ارزان‌تر است = chicken is cheaper

This is the normal way to say more/‑er with adjectives in Persian.

Yes. از often means from, but in comparative sentences it also means than.

The pattern is:

X از Y adjective+تر است
= X is more adjective than Y

So:

این گوشت از آن یکی گران‌تر است
literally follows the pattern
this meat than that one expensive-more is

So in this sentence, از is the word that introduces the thing being compared, just like than in English.

آن یکی means that one or the other one, depending on context.

• آن = that
• یکی = one

So از آن یکی means than that one / than the other one.

In natural English, if two kinds of meat are being compared, the other one may sound better. But grammatically, that one is also a correct way to understand it.

Because یکی can stand in for a noun that is already understood from context.

English does the same:

• this meat is more expensive than that one

You do not need to repeat meat. Persian works similarly:

• این گوشت از آن یکی گران‌تر است

The full noun is omitted because it is obvious.

In context, مرغ here means chicken as food, not just the live animal.

That is very normal in Persian. Depending on context, مرغ can mean:

• a chicken
• chicken meat

Since the sentence is comparing prices of food, the meaning is clearly chicken meat / chicken.

A useful note: گوشت means meat, and in everyday usage it can often suggest non-chicken meat unless the type is specified. So the contrast between گوشت and مرغ makes good sense in Persian.

In Persian, the verb است = is usually comes at the end of the clause.

So:

• گران‌تر است = is more expensive
• ارزان‌تر است = is cheaper

This is normal Persian word order. The adjective comes before است, not after it.

So the structure is:

• این گوشت ... گران‌تر است
• مرغ ارزان‌تر است

Yes. In spoken Persian, است is often replaced or dropped in a more colloquial form.

A natural spoken version would be something like:

این گوشت از اون یکی گرون‌تره، اما مرغ ارزون‌تره.

Changes you often hear in speech:

• آن → اون
• گران → گرون
• ارزان → ارزون
• است → ـه

So the written sentence is formal/standard, while the spoken version sounds more everyday.

Good question. In careful modern writing, ـتر is usually written attached with a half-space:

• گران‌تر
• ارزان‌تر

But in informal writing, many people write it with a normal space:

• گران تر
• ارزان تر

Both mean the same thing. The version with the half-space is generally considered more standard.

Because Persian adjectives do not work like English adjectives that sometimes interact with special forms, and they definitely do not change for grammatical gender the way adjectives do in many European languages.

So گران‌تر stays گران‌تر no matter what noun it describes:

• masculine/feminine: no change
• singular/plural: usually no change

That makes Persian comparatives fairly simple.

Yes, it is very typical.

The sentence is:

این گوشت | از آن یکی | گران‌تر است، | اما | مرغ | ارزان‌تر است.

A natural breakdown is:

• این گوشت = this meat
• از آن یکی = than that one
• گران‌تر است = is more expensive
• اما = but
• مرغ ارزان‌تر است = chicken is cheaper

So Persian often puts the comparison phrase before the adjective, and the verb است comes at the end of each clause.

Yes. That is very common in speech.

• آن یکی = more formal / written
• اون یکی = more conversational / spoken

So these are both natural, but they fit different styles:

• Written/standard: این گوشت از آن یکی گران‌تر است
• Spoken: این گوشت از اون یکی گرون‌تره

Both mean the same thing.