יורה דעה ג׳Yoreh De'ah 3

Se’if 1א׳

שְׁחִיטַת חֻלִּין אֵינָהּ צְרִיכָה כַּוָּנָה. אֲפִלּוּ מִתְעַסֵק בְּעָלְמָא לַחְתֹּךְ, אוֹ שֶזָּרַק סַכִּין לְנוֹעֲצָהּ בַּכֹּתֶל, וְשָׁחֲטָה כְּהִלְכָתָהּ (ס"א בַּהֲלִיכָתָהּ וְעִקָר), כְּשֵׁרָה. וְהוּא שֶׁרָאָה שֶׁלֹּא הֶחְלִיד (פי' עִנְיָן נְעִיצָה וּתְחִיבָה, מִלְּשׁוֹן חֻלְדָּה, שֶׁנִּכְנֶסֶת בַּחוֹרִין וּבַסְדָקִין) הַסַכִּין בֵּין סִימָן לְסִימָן, אוֹ תַּחַת הָעוֹר. וְאִם מָצָא הַנּוֹצָה אוֹ הַשֵּׂעָר חֲתוּכִים, וַדַּאי לֹא הֶחְלִיד. וַאֲפִלּוּ הִפִּיל הַסַכִּין בְּיָדוֹ, אוֹ בְּרַגְלוֹ, שֶׁלֹּא בְּכַוָּנָה כְּלָל, וְשָׁחַט, שְׁחִיטָתוֹ כְּשֵׁרָה. אֲבָל אִם נָפְלָה מֵעַצְמָהּ, פְּסוּלָה, דִּבְעִינָן כֹּחַ גַּבְרָא (ע"ל סי' ז'). וְכֵן אִם הָיָה הַסַכִּין מֻנָּח בְּחֵיקוֹ אוֹ בְּיָדוֹ, וְנָפְלָה מִיָּדוֹ אוֹ מֵחֵיקוֹ שֶׁלֹּא בְּכַוָּנָה, כְּנָפְלָה מֵעַצְמָהּ דָּמֵי, וּפְסוּלָה.

The slaughter of unconsecrated animals does not require intention. Even where he acts unawares (mitasek — one who performs the act without intending it), merely to cut, or where he threw a knife to fix it in the wall and it slaughtered in the proper manner (another reading: "in its going", and that is the principal one) — it is valid. And that is provided that he saw that he did not thrust the knife in — chaladah (that is, a matter of sticking in and thrusting in, from the word chuldah, a weasel, which enters into holes and crevices) — between one siman and the other, the simanim being the windpipe and the gullet, which the slaughter must sever, or beneath the hide. And if he found the feather or the hair cut through, certainly he did not thrust it in. And even if he let the knife fall with his hand or with his foot, with no intention at all, and he slaughtered, his slaughter is valid. But if it fell of itself, it is invalid, for we require a man's own power. (See below, siman 7.) And likewise if the knife was lying in his bosom or in his hand and it fell from his hand or from his bosom without intention, it is as one that fell of itself, and it is invalid.