(24) You shall not offer to GOD anything [with its testes] bruised or crushed or torn or cut. You shall have no such practices in your own land, (25) nor shall you accept such [animals] from a foreigner for offering as food for your God, for they are mutilated, they have a defect; they shall not be accepted in your favor.

(11) "You shall not offer": This tells me only of offering. Whence is derived the prohibition of doing? The Torah teaches "you shall not do this."... This tells me only of a domesticated animal. Whence do I derive a wild animal and a bird? From "in your land." This tells me only of in the land. Whence do I derive outside of the land? From "you shall not do this".

(12) Whence is it derived that females are subject to [the prohibition of] neutering? From "for their corruption is in them; a blemish is in them." R. Yehudah says: "in them" (masculine) — Females are not subject to [the prohibition of] neutering...

They asked ben Zoma: What is the halakha with regard to castrating a dog?He said to them: The verse states “That which has its testicles bruised, or crushed, or torn, or cut, you shall not offer to God, nor shall you do so in your land” (Leviticus 22:24): With regard to any animal that is in your land, you shall not do such a thing.

Not to castrate a male from any species - neither a human, a domestic animal, a wild beast, nor a bird, as [Leviticus 22:24] states: "You shall not do this in your land."

A person who castrates a female - whether a human or other species - is not liable.

It is prohibited to cause the loss of the seminal organs, whether regarding a human, domesticated animal, wild animal, bird, whether kosher or not, whether in the land of Israel or the diaspora. Anyone who castrates is lashed according to the Torah, in any place. Even one who castrates after a castration is lashed. How so? One comes and severs the penis, and another comes and severs the testicles or pulls them out, and another comes and severs the testicular tracts. Or one comes and crushes the penis, and another comes and pulls out [his testicles] , and another comes and severs it. All are lashed, even though the last castrator did not [truly] castrate, whether regarding a human, a domesticated animal, wild animal, or bird. One who castrates a female, whether human or the other species, is exempt (Rama: but forbidden).

Rabbi Yoḥanan said: One who seeks to castrate a rooster should remove its comb and it will become castrated on its own.Didn’t Rav Ashi say: It is arrogance that it assumes when it has its comb, and when the comb is removed it becomes depressed and no longer procreates. However, it is not actually castrated.

Rabbi Ḥideka says: The descendants of Noah are also commanded concerning castration, i.e., they are prohibited to castrate any living animal.

A dilemma was raised before the Sages: What is the halakha with regard to the possibility that a person can say to a gentile: Muzzle my cow and thresh with it? Do we say that when we state the principle that speaking to a gentile and requesting of him to perform for oneself a task forbidden to a Jew is prohibited by a rabbinic decree, this matter applies only to Shabbat, when the performance of labor is a prohibition that entails stoning, but with regard to muzzling, which is merely a regular prohibition, giving an instruction of this kind to a gentile is not prohibited; or perhaps there is no difference between the prohibitions of Shabbat and other prohibitions in this regard? ... Come and hear, as they sent to Shmuel’s father a halakhic inquiry with regard to these oxenwhich gentiles steal and castrate. Since it is prohibited for Jews to castrate animals, they would sometimes arrange for a gentile to pretend to steal the animal and subsequently return it after castrating it, as it is easier to handle a castrated animal. What is the halakha with regard to a case of this kind? Shmuel’s father sent to him: They used artifice; therefore, you should use artifice with them and make them sell it as a punishment. This shows that it is prohibited to instruct a gentile to perform a prohibition on one’s behalf. Rav Pappa said: This provides no conclusive proof, as the inhabitants of the West, i.e., Eretz Yisrael, who are the ones who raised this question, hold in accordance with the opinion of Rabbi Ḥideka, who says: The descendants of Noah are commanded with regard to castration. They too are prohibited from performing this practice. And consequently, those Jews who cause them to do it transgress the prohibition of: “Nor put a stumbling block before the blind” (Leviticus 19:14). Rava thought to say that it is not enough that the owners may not use these animals castrated for them by gentiles, but they must even sell the animals for slaughter, but not for plowing, so that they would derive no benefit at all from the increase in the value of their property that resulted from a transgression. A castrated animal is worth more if it is sold for plowing, but not if it is sold for slaughter. Abaye said to him: It is enough for them that you penalized them by requiring them to sell the animals. With regard to the same issue, the Gemara comments: It is obvious that if one sold the castrated animal to his adult son, the son is considered like another person, i.e., there is no need to sell to a complete stranger. If the buyer was his minor son, what is the halakha? Rav Aḥai prohibited this, and Rav Ashi permitted it. Mareimar and Mar Zutra, and some say it was a certain pair of unknown pious men, would exchange such oxen with each other.

It is forbidden to tell a gentile to castrate one of our animals. If the gentile took the animal and castrated it on his own initiative, it is permitted. If a Jew acts deceitfully in this context, he should be punished and required to sell the animal to another Jew. He may [sell it] to his son who is past majority, but not to his son who is below majority, nor may he give it to him.

Rema

It is permitted to take hold of the crest of a rooster, even though it will be castrated through it, and anything else like that, because nothing was done to the seminal organs.