Begin from the original form of torture and become immortal

Chapter 566 The Reproduction and Growth Cycle of Orcs
Xizhe's entry in the appendix talks about the enemies who initially supported Rohan - so these would be the Dunlanders.

If we quote from Unfinished Stories, we see that Tolkien stated that the use of orcs and possible special breeding did not begin before 2990 (so around the time he investigated the True Seeing Stone).

This makes the picture very clear: first allied with the Dunlanders, only after contact with Sauron did he fall completely and start building an army of orcs.

Secondly, if Tolkien is correct about the "breeding program" starting in 2990, then as commenters pointed out, the Orcs and Uruk-hai of Bree would have reached adulthood in 28 years (assuming they were like humans Same aging)).

It's possible that the first Orcs and Orcs were born in 2990, so the second "batch" could be born in 3000, making the Orc army/Orc spies around 18 years old, but thought to be more likely , Saruman's Uruk navy and Orc CIA are all between 20 and 30 years old.

It's actually worse: the first generation needs to become fertile again before the second generation (if we assume Saruman's orcs are 1/4 human) can start being made.

The use and possible special breeding of orcs has been kept secret and is unlikely to begin before the year 2990 at the earliest.

Prior to the attack on Rohan, the orc armies appear to have never been used outside of Isengard territory.

If the Council knew this, of course they would immediately realize that Saruman had become evil.

So Saruman began to build his army of Orcs about 30 years before the War of the Ring.

Around the time he used the Seeing Stone and formed a bond with Sauron.

This time it was necessary, as he still had to conduct breeding experiments to create Orcs (which were not Orcs!).

He first obtained a large number of orcs from Sauron, and then began to breed under the pits of Isengard.

It was during these early years that he began his evil experiments, which led to the creation of the Orcs.

But Orcs are not Orcs, because you don't have time to build an army of thousands of specially bred Orcs in such a short period of time.

Orcs have sallow skin and are as big as humans, while Orcs have dark skin and are slightly shorter.

It would take generations to have black skin, which Saruman did not have.

This is the first generation of Orcs we see in Saruman's army, with the second generation not yet coming of age at this point.

However, a side note to the unfinished story is that the addendum does contradict the claim that orcs were never used in the territory of Rohan.

In 2989, Théodwyn married Mark's chief marshal, Eomund.

In 2991, her son Omer was born, and in 2995, her daughter Eowen was born.

Then Sauron rose again, and the shadow of Mordor stretched over Rohan.

Orcs began raiding the eastern lands and slaughtering or stealing horses.

Others also descended from the Misty Mountains, many of them great Uruk-men in the service of Saruman, although this was suspected long ago.

Éomund's chief responsibility was to the Eastern Marches; he was a great lover of horses and a hater of orcs.

If news of an attack came, he would usually ride against them in anger, carelessness, and small numbers.

Accordingly, he was killed in 3002; for he pursued a small band of men as far as the borders of the river Emin Mui, but was surprised by a powerful force lying in wait among the rocks.
-
LotR, Appendix A
This does mean that Saruman not only used the pits of Isengard as a breeding ground for his armies, but also traveled deep into the Misty Mountains.This greatly enhances the realism of the situation: you can't fit, train and feed an army of 10.000 orcs in such a small space (although he certainly did that in Isengard - especially for Controlling his orc experiments).

This problem can be easily solved by using the caves in the southern part of the Misty Mountains.

All lands west of the North-South Road, including the ancient elven kingdom of Eregion, were laid waste.There is very little traffic on the road and one would not risk leaving it.

So you could hide a sizable orc colony there and use the surrounding land to feed them.

If the orcs preferred mountains, his Uruk-hai could be established in the Misty Mountains north of Isengard.No one has ever been to this area.

But some people think this is not a good choice because the giant eagle is in the mountains and they will see new orc activity.

It is best to give birth on the plains.

Saruman is not only an industrial pioneer in Middle-earth, he is also a genetics expert in Middle-earth. He may have forced the Dunlanders to crossbreed with orcs. This is obviously a bad practice, whether for orc women or human women. It's all a nightmare.

There is also a theory about the breeding of orcs. They are created from the earth. This is vividly shown in the "Lord of the Rings" movies. We can see the orcs being pulled out of the earth and the way they grow up is As if from the cocoon, they are ready to be dug out, is this really the case?

This method of birth is as simple as using a potion formula. If you only need a part of the orc's body, you can keep watering it, and then five orcs can grow in the original position. This also explains why the orcs reproduce so quickly. And with such a large number, you may wonder why this is the case, because this is just a guess on our part and we have no confirmation from Tolkien.

Now Changwei follows Saruman's lead, and the green orcs take about the same amount of time to grow as the strong orcs.

Saruman was very surprised when he heard that a brand new creature had appeared.

Then he tried to have his orcs and orcs capture a few green orcs to show him.

After all, Saruman, as a technological pioneer in Middle-earth, had little interest in unknown creatures.

"Oh? Orcs and half-orcs are encircling you?"

Chang Wei played with the Supreme Lord of the Rings, wondering whether to create an orc with the Eighteen Rings, but it seemed that it was not right.

Since the Lord of the Rings are all in odd numbers, it should be the twelve or fifteen ring of the orcs.

Hearing that Saruman had dispatched the orcs, Chang Wei immediately understood what Saruman was thinking.

Saruman would not easily dispatch his army of orcs.

"Your Majesty, we are not afraid of them!"

The "boss" of the green orcs said excitedly to Chang Wei.

"How many times have I told you, don't call me King, call me His Majesty the Emperor!"

Chang Wei struck the "boss" with a bolt of lightning until he fell to the ground, black and smoking.

The green orcs around them trembled for a moment, and then became even more excited.

(End of this chapter)