Mishnayos Bechoros Perek 9 Mishnah 7

In what manner does one tithe the animals? He gathers them in a pen and provides them with a small, i.e., narrow, opening, so that two animals will not be able to emerge together. And he counts the animals as they emerge: One, two, three, four, five, six, seven, eight, nine; and he paints the animal that emerges tenth with red paint and declares: This is tithe. Even if he did not paint it with red paint, or if he did not count the animals with a rod in accordance with the verse: “Whatever passes under the rod, the tenth shall be sacred to the Lord” (Leviticus 27:32), or if he counted the animals when they were prone or standing in place and did not make them pass through a narrow opening, these animals are tithed after the fact. But if he had one hundred animals and he took ten as tithe, or if he had ten animals and he simply took one as tithe, that is not tithe, as he did not count them one by one until reaching ten. Rabbi Yosei, son of Rabbi Yehuda, says: In that case too, it is tithe. If before the owner completed tithing his animals, one of those already counted jumped back into the pen among the animals that had not yet been counted, all those in the pen are exempt from being tithed, as each of them might be the animal that was already counted. If one of those animals that had been tithed, i.e., designated as the tenth, jumped back into the pen among the animals that had not yet been counted, creating uncertainty with regard to all the animals there which was the animal tithe, all the animals must graze until they become unfit for sacrifice, and each of them may be eaten in its blemished state by its owner once it develops a blemish.

כֵּיצַד מְעַשְּׂרָן, כּוֹנְסָן לַדִּיר וְעוֹשֶׂה לָהֶן פֶּתַח קָטָן כְּדֵי שֶׁלֹּא יִהְיוּ שְׁנַיִם יְכוֹלִין לָצֵאת כְּאַחַת, וּמוֹנֶה בַשֵּׁבֶט, אֶחָד, שְׁנַיִם, שְׁלשָׁה, אַרְבָּעָה, חֲמִשָּׁה, שִׁשָּׁה, שִׁבְעָה, שְׁמוֹנָה, תִּשְׁעָה, וְהַיוֹצֵא עֲשִׂירִי סוֹקְרוֹ בְסִקְרָא וְאוֹמֵר הֲרֵי זֶה מַעֲשֵׂר. לֹא סְקָרוֹ בְסִקְרָא וְלֹא מְנָאָם בַּשֵּׁבֶט, אוֹ שֶׁמְּנָאָם רְבוּצִים, אוֹ עוֹמְדִים, הֲרֵי אֵלּוּ מְעֻשָּׂרִים, הָיָה לוֹ מֵאָה וְנָטַל עֲשָׂרָה, עֲשָׂרָה וְנָטַל אֶחָד, אֵין זֶה מַעֲשֵׂר. רַבִּי יוֹסֵי בְּרַבִּי יְהוּדָה אוֹמֵר, הֲרֵי זֶה מַעֲשֵׂר, קָפַץ (אֶחָד) מִן הַמְּנוּיִין לְתוֹכָן, הֲרֵי אֵלּוּ פְטוּרִין. מִן הַמְעֻשָּׂרִים לְתוֹכָן, כֻּלָּן יִרְעוּ עַד שֶׁיִּסְתָּאֲבוּ, וְיֵאָכְלוּ בְמוּמָן לַבְּעָלִים: