The Mishnah
חולין ב׳Chullin 2
Perek 2 of 12 in Chullin — 10 mishnayot
Mishnah 1א׳
הַשּׁוֹחֵט אֶחָד בָּעוֹף, וּשְׁנַיִם בַּבְּהֵמָה, שְׁחִיטָתוֹ כְשֵׁרָה. וְרֻבּוֹ שֶׁל אֶחָד, כָּמוֹהוּ. רַבִּי יְהוּדָה אוֹמֵר, עַד שֶׁיִּשְׁחֹט אֶת הַוְּרִידִין. חֲצִי אֶחָד בָּעוֹף, וְאֶחָד וָחֵצִי בַּבְּהֵמָה, שְׁחִיטָתוֹ פְסוּלָה. רֹב אֶחָד בָּעוֹף וְרֹב שְׁנַיִם בַּבְּהֵמָה, שְׁחִיטָתוֹ כְשֵׁרָה:
One who slaughters one [of either the trachea or esophagus] for a bird, and both for cattle, his slaughter is valid. The majority of one [of the trachea or esophagus] is like [all of] it. Rabbi Yehuda says, "[Not] until he cuts the jugular veins." [If he cut] one half of one for a bird, and one and a half for cattle, his slaughter is unfit. [If he cut] the majority of one for a bird, and the majority of two for cattle, his slaughter is valid.
Mishnah 2ב׳
הַשּׁוֹחֵט שְׁנֵי רָאשִׁין כְּאֶחָד, שְׁחִיטָתוֹ כְשֵׁרָה. שְׁנַיִם אוֹחֲזִין בַּסַּכִּין וְשׁוֹחֲטִין, אֲפִלּוּ אֶחָד לְמַעְלָה וְאֶחָד לְמַטָּה, שְׁחִיטָתָן כְּשֵׁרָה:
One who slaughters two heads in one, his slaughter is valid. When two hold the knife and slaughter, even if one [held it] at the top and one at the bottom, their slaughter is valid.
Mishnah, Torat Emet 357 edition, via Sefaria — public domain
English: Sefaria Community Translation — CC0