Reference for Chullin 1:1
הַכֹּל שׁוֹחֲטִין וּשְׁחִיטָתָן כְּשֵׁרָה, חוּץ מֵחֵרֵשׁ, שׁוֹטֶה, וְקָטָן, שֶׁמָּא יְקַלְקְלוּ בִשְׁחִיטָתָן. וְכֻלָּן שֶׁשָּׁחֲטוּ וַאֲחֵרִים רוֹאִין אוֹתָן, שְׁחִיטָתָן כְּשֵׁרָה. שְׁחִיטַת נָכְרִי, נְבֵלָה, וּמְטַמְּאָה בְמַשָּׂא. הַשּׁוֹחֵט בַּלַּיְלָה, וְכֵן הַסּוּמָא שֶׁשָּׁחַט, שְׁחִיטָתוֹ כְשֵׁרָה. הַשּׁוֹחֵט בְּשַׁבָּת, וּבְיוֹם הַכִּפּוּרִים, אַף עַל פִּי שֶׁמִּתְחַיֵּב בְּנַפְשׁוֹ, שְׁחִיטָתוֹ כְשֵׁרָה:
Everyone [may] slaughter and his slaughter is valid, except [that of] a deafmute, a simpleton or a minor, so that they will not spoil the slaughter [i.e., make a mistake]. But [if they] all slaughter and others see them, their slaughter is valid. The slaughter of a non-Jew - it is a nevelah and has the uncleanness of carry-on. [If] the slaughterer [slaughters] at night and thereby his slaughter is blind, his slaughter is valid. [If] the slaughterer [slaughters] on Shabbat, or on Yom Kippur - even though he is liable for his soul - his slaughter is valid.