Animals in Judaism

Tza'ar ba'alei chayim (literally means: "the suffering of living creatures") is the Jewish principle which bans inflicting unnecessary pain on animals.
This concept is not clearly enunciated in the written Torah, but was accepted by the Talmud (Bava Metzia 32b) as being a Biblical mandate.
It is linked in the Talmud from the Biblical law requiring people to assist in unloading burdens from animals (Exodus 23:5).
This concept is not clearly enunciated in the written Torah, but was accepted by the Talmud (Bava Metzia 32b) as being a Biblical mandate.
It is linked in the Talmud from the Biblical law requiring people to assist in unloading burdens from animals (Exodus 23:5).

Treatment of animals killed for food
Humane Slaughter of Animals In traditional Jewish law, animals may be eaten as long as they are killed as painlessly and humanely as possible using the method known as shechitah, where the animal is killed by having its throat cut swiftly using a specially sharpened knife. Jewish authorities have asserted that shechitah is the least painful method of slaughter possible.
In 2000, the Rabbinical Assembly of Conservative Judaism's Committee on Jewish Law and Standards banned the common slaughter method of "shackling and hoisting" (pulling a conscious animal into the air with a chain before slaughter).
Rabbis Joel Roth and Elliot Dorff wrote a responsum on this topic which concluded that shackling and hoisting "unquestionably constitutes a violation of Jewish laws that forbid us to cause undue pain to animals."
Hekhsher Tzedek Enforcing a commitment to tza'ar ba'alei chayim in food production has been part of the effort of Conservative Judaism's Hekhsher Tzedek commission. The Hekhsher Tzedek commission sees compliance with the Humane Farm Animal Care Standards (HFAC) as sufficiently preventing unnecessary suffering to animals.
Humane Slaughter of Animals In traditional Jewish law, animals may be eaten as long as they are killed as painlessly and humanely as possible using the method known as shechitah, where the animal is killed by having its throat cut swiftly using a specially sharpened knife. Jewish authorities have asserted that shechitah is the least painful method of slaughter possible.
In 2000, the Rabbinical Assembly of Conservative Judaism's Committee on Jewish Law and Standards banned the common slaughter method of "shackling and hoisting" (pulling a conscious animal into the air with a chain before slaughter).
Rabbis Joel Roth and Elliot Dorff wrote a responsum on this topic which concluded that shackling and hoisting "unquestionably constitutes a violation of Jewish laws that forbid us to cause undue pain to animals."
Hekhsher Tzedek Enforcing a commitment to tza'ar ba'alei chayim in food production has been part of the effort of Conservative Judaism's Hekhsher Tzedek commission. The Hekhsher Tzedek commission sees compliance with the Humane Farm Animal Care Standards (HFAC) as sufficiently preventing unnecessary suffering to animals.

The Hebrew term shechita, also transliterated shehitah, shechitah, shehita, means the slaughtering of mammals and birds for food. In Hebrew the word is generic and does not imply any religious or cultural practice, but in English the term has come to be used particularly for "kosher slaughter", that is the slaughter of animals for food according to Jewish dietary laws (Deut. 12:21, Deut. 14:21, Num. 11:22).
The animal must be killed "with respect and compassion" by a religious Jew who is duly licensed and trained, often called in English a shochet (Hebrew: שוחט) although in Hebrew this word refers to a butcher regardless of any particular religion or culture.
The act is performed by severing the trachea, esophagus, carotid arteries, jugular veins and vagus nerve in a swift action using an extremely sharp blade ("chalef") only by a qualified shochet. According to Jewish religious sources, this results in a rapid drop in blood pressure in the brain and loss of consciousness rendering the animal insensible to pain and to exsanguinate in a prompt and precise action. The animal can be in a number of positions; when the animal is lying on its back, this is referred to as shechita munachat; in a standing position it is known as shechita me'umedet. Before slaughtering, the animal must be healthy, uninjured, and viable.
If the hindquarters of kosher mammals are to be eaten by Jews, they must be porged in accordance with a strict procedure – stripped of veins, chelev (caul fat and suet) and sinews. Because of the expense of porging and the skill required to properly separate out the forbidden parts, a large portion of the meat of kosher mammals slaughtered through shechita in the United States winds up on the non-kosher market.
The animal must be killed "with respect and compassion" by a religious Jew who is duly licensed and trained, often called in English a shochet (Hebrew: שוחט) although in Hebrew this word refers to a butcher regardless of any particular religion or culture.
The act is performed by severing the trachea, esophagus, carotid arteries, jugular veins and vagus nerve in a swift action using an extremely sharp blade ("chalef") only by a qualified shochet. According to Jewish religious sources, this results in a rapid drop in blood pressure in the brain and loss of consciousness rendering the animal insensible to pain and to exsanguinate in a prompt and precise action. The animal can be in a number of positions; when the animal is lying on its back, this is referred to as shechita munachat; in a standing position it is known as shechita me'umedet. Before slaughtering, the animal must be healthy, uninjured, and viable.
If the hindquarters of kosher mammals are to be eaten by Jews, they must be porged in accordance with a strict procedure – stripped of veins, chelev (caul fat and suet) and sinews. Because of the expense of porging and the skill required to properly separate out the forbidden parts, a large portion of the meat of kosher mammals slaughtered through shechita in the United States winds up on the non-kosher market.
Preparation

The animal must be kosher. For mammals, this is restricted to ruminants which have split hooves. For birds the issue is more complicated. Biblically, all birds not specifically excluded in Deuteronomy 14:12–18 are permitted, but according to some authorities of rabbinical law, only birds with a tradition of being eaten are allowed.
The kosher animal cannot be shot dead by a hunter, or pollaxed, which had been common for centuries, or stunned, as is common practice in modern animal slaughter since the first half of the twentieth century, as it is considered that this would injure the animal rendering the shechita invalid, as the meat would be treifa (non-Kosher).
After shechita of mammals the shochet must feel the area around the lungs for scabbing, adhesions or other lesions, which would render the animal not kosher.
Sources
The Torah (Deut. 12:21) states that sheep and cattle should be slaughtered 'as I have commanded thee' but nowhere in the Torah (Five books of Moses) are any of the practices of schechita described. Instead, they have been handed down in Judaism's traditional Oral Torah, and codified in halakha in various sources, most notably the canonical codex of laws Shulchan Aruch.
The kosher animal cannot be shot dead by a hunter, or pollaxed, which had been common for centuries, or stunned, as is common practice in modern animal slaughter since the first half of the twentieth century, as it is considered that this would injure the animal rendering the shechita invalid, as the meat would be treifa (non-Kosher).
After shechita of mammals the shochet must feel the area around the lungs for scabbing, adhesions or other lesions, which would render the animal not kosher.
Sources
The Torah (Deut. 12:21) states that sheep and cattle should be slaughtered 'as I have commanded thee' but nowhere in the Torah (Five books of Moses) are any of the practices of schechita described. Instead, they have been handed down in Judaism's traditional Oral Torah, and codified in halakha in various sources, most notably the canonical codex of laws Shulchan Aruch.
Duties of the shochet
To fulfill the basic law of shechita, the majority of both the trachea and esophagus (windpipe and food pipe) of a mammal, or the majority of either one of these in the case of birds, must be incised with a back and forth motion without violating one of the five major prohibited techniques, or various more detailed rules.
The five major forbidden techniques include: pressing, pausing, tearing, piercing, or covering. A shochet must have studied these laws and demonstrate a thorough understanding of them, as well as have been carefully trained, before he is allowed to 'shekht' meat unaided.
To fulfill the basic law of shechita, the majority of both the trachea and esophagus (windpipe and food pipe) of a mammal, or the majority of either one of these in the case of birds, must be incised with a back and forth motion without violating one of the five major prohibited techniques, or various more detailed rules.
The five major forbidden techniques include: pressing, pausing, tearing, piercing, or covering. A shochet must have studied these laws and demonstrate a thorough understanding of them, as well as have been carefully trained, before he is allowed to 'shekht' meat unaided.
Animal Research

According to the Shulkhan Aruch,"anything that is necessary for medical purposes, or for anything else, is exempt from the prohibition of causing suffering to animals" (Even ha-Ezer 5:14).
Most Jewish authorities allow medical research if it will help people in need, and if the animals do not undergo any unnecessary suffering. Reform Judaism's Central Conference of American Rabbis, for example, affirms that animal research is permissible if it will save human lives, so long as animals are subjected to little pain and not used in “frivolous” experiments such as cosmetic testing.
Other areas of concern for animals in Jewish law
Resting on the Sabbath also meant providing rest for the working animals, and people are instructed to feed their animals before they sit down to eat. At harvest time, the working animals must not be muzzled, so that they can eat of the harvest as they work.
Sports like bullfighting are forbidden by most authorities. Rabbi Ovadia Yosef has characterized bullfighting as “a culture of sinful and cruel people” which is opposed by Torah values. Most authorities oppose recreational hunting on similar grounds.
Some oppose kapparot, a ritual of swinging live chickens over people's heads, on the grounds of Tza'ar ba'alei chayim. All animals must be kept in adequate conditions.
Most Jewish authorities allow medical research if it will help people in need, and if the animals do not undergo any unnecessary suffering. Reform Judaism's Central Conference of American Rabbis, for example, affirms that animal research is permissible if it will save human lives, so long as animals are subjected to little pain and not used in “frivolous” experiments such as cosmetic testing.
Other areas of concern for animals in Jewish law
Resting on the Sabbath also meant providing rest for the working animals, and people are instructed to feed their animals before they sit down to eat. At harvest time, the working animals must not be muzzled, so that they can eat of the harvest as they work.
Sports like bullfighting are forbidden by most authorities. Rabbi Ovadia Yosef has characterized bullfighting as “a culture of sinful and cruel people” which is opposed by Torah values. Most authorities oppose recreational hunting on similar grounds.
Some oppose kapparot, a ritual of swinging live chickens over people's heads, on the grounds of Tza'ar ba'alei chayim. All animals must be kept in adequate conditions.

Concern for Animal Suffering in the Noachide Code
A concern for suffering caused to animals is found in Judaism's Seven Laws of Noah, which apply to all mankind. One of the seven laws prohibits eating a limb from a living animal. This law is derived from Genesis 9:4, as interpreted in the Talmud (Sanhedrin 59a).
Tza'ar ba'alei chayim in Jewish Lore
Compassion for animals is declared to have been the merit of Moses which made him the shepherd of his people (Exodus Rabbah 2), while Judah ha-Nasi saw in his own ailment the punishment for having once failed to show compassion for a frightened calf - source
A concern for suffering caused to animals is found in Judaism's Seven Laws of Noah, which apply to all mankind. One of the seven laws prohibits eating a limb from a living animal. This law is derived from Genesis 9:4, as interpreted in the Talmud (Sanhedrin 59a).
Tza'ar ba'alei chayim in Jewish Lore
Compassion for animals is declared to have been the merit of Moses which made him the shepherd of his people (Exodus Rabbah 2), while Judah ha-Nasi saw in his own ailment the punishment for having once failed to show compassion for a frightened calf - source