Zevachim 73b

וְכׇל קָבוּעַ כְּמֶחֱצָה עַל מֶחֱצָה דָּמֵי! אֶלָּא נִיכְבְּשִׁינְהוּ (דְּנָיְידִי) [דְּנִינַיְידָּן], וְנֵימָא: כֹּל דְּפָרֵישׁ – מֵרוּבָּא פָּרֵישׁ!

and there is a principle that anything fixed is considered as though it was half and half, i.e., equally balanced, and it remains a case of uncertainty. The Gemara clarifies its suggestion: Rather, let us push the intermingled animals so that they all move from their places, which negates the fixed status of the prohibited item. And accordingly, let us say with regard to each animal: Any item that separates from a group is assumed to have separated from the majority.

אָמַר רָבָא: הַשְׁתָּא דַּאֲמוּר רַבָּנַן לָא נִיקְרַב, גְּזֵירָה שֶׁמָּא יָבֹאוּ עֲשָׂרָה כֹּהֲנִים בְּבַת אַחַת וְיַקְרִבוּ.

Rava says: Now that the Sages have said that we do not sacrifice any of them, this is evidently a rabbinic decree, lest ten priests come simultaneously and sacrifice all the animals in the mixture together, not one at a time. Therefore, the fact that there could be a method to permit the animals is immaterial.

אֲמַר לֵיהּ הָהוּא מֵרַבָּנַן לְרָבָא: אֶלָּא מֵעַתָּה, מְגִיסָא אֲסִירָא?!

One of the Sages said to Rava: If that is so, do you hold that the large basin [ megisa ] on which the sacrificial portions of the animal are placed is prohibited? In other words, is it possible that these animals, which were slaughtered when they were initially declared permitted after being separated from their places, could later become prohibited again when their sacrificial portions are ready to be burned on the altar?

מִשּׁוּם שֶׁמָּא יָבֹאוּ עֲשָׂרָה כֹּהֲנִים בְּבַת אַחַת וְיִקְחוּ. בַּעֲשָׂרָה כֹּהֲנִים בְּבַת אַחַת מִי אֶפְשָׁר?! אֶלָּא אָמַר רָבָא: מִשּׁוּם קָבוּעַ.

Rava responded that he did not mean there is a concern that ten priests would sacrifice their sacrificial portions simultaneously. Rather, the decree is due to the concern lest when the animals move, ten priests will come simultaneously and take them from the mixture. As all or most of the animals were separated simultaneously in this case, it is assumed that the prohibited animal is among those that were separated. The Gemara asks: Is it possible for ten priests to take these scattered animals simultaneously? Rather, Rava says that one may not allow the animals to be sacrificed by moving them due to a decree that if this is allowed, one may, in another circumstance, allow them to be sacrificed even when they are taken from a fixed location.

אָמַר רָבָא: הַשְׁתָּא דְּאָמְרִי רַבָּנַן לָא נַקְרֵיב, אִי (נַקְרֵיב) [מַקְרֵיב] – לָא מְרַצֵּי. אֵיתִיבֵיהּ רַב הוּנָא בַּר יְהוּדָה לְרָבָא: חַטָּאת שֶׁנִּתְעָרְבָה בְּעוֹלָה, וְעוֹלָה שֶׁנִּתְעָרְבָה בְּחַטָּאת, אֲפִילּוּ אַחַת בְּרִיבּוֹא – יָמוּתוּ כּוּלָּן.

§ Rava said: Now that the Sages say in the mishna that we do not sacrifice any of the animals, if we did sacrifice one of them, the offering does not effect acceptance for the owner. Rav Huna bar Yehuda raised an objection to Rava from a mishna ( Kinnim 22b): With regard to a bird sin offering that was intermingled with a bird burnt offering, or a bird burnt offering that was intermingled with a bird sin offering, even if the ratio is one in ten thousand, they all must die, as there is no remedy for these birds. It is not known which is which, and their sacrificial rites are performed differently.

בַּמֶּה דְּבָרִים אֲמוּרִים – בְּכֹהֵן נִמְלָךְ; אֲבָל בְּכֹהֵן שֶׁאֵין נִמְלָךְ, עֲשָׂאָן לְמַעְלָה – מֶחֱצָה כָּשֵׁר וּמֶחֱצָה פָּסוּל.

The mishna continues: In what case is this statement said? In the case of a priest who consulted the court to ask how he should proceed. But in the case of a priest who did not consult the court, but sacrificed them of his own accord, if there was an equal number of bird sin offerings and burnt offerings, and he performed all their sacrificial rites above the red line that circumscribes the altar at its midpoint, as required for a burnt offering, half of the birds are fit, as in any event the burnt offerings were sacrificed properly, and half are unfit.

לְמַטָּה – מֶחֱצָה כָּשֵׁר וּמֶחֱצָה פָּסוּל. אַחַת לְמַטָּה וְאַחַת לְמַעְלָה – (שְׁנֵיהֶן) [שְׁתֵּיהֶן] פְּסוּלוֹת, שֶׁאֲנִי אוֹמֵר: חַטָּאת קְרֵיבָה לְמַעְלָה וְעוֹלָה קְרֵיבָה לְמַטָּה.

Likewise, if he performed all of their sacrificial rites below the red line, half are fit, as in any event the sin offerings were sacrificed properly, and half are unfit. If he performed the sacrificial rites of one of the birds below the red line and one of the birds above the red line, they are both unfit, as I say that the sin offering was sacrificed above the red line and the burnt offering was sacrificed below. This mishna proves that an offering that is prohibited to be sacrificed as part of a mixture is fit after the fact, which contradicts the statement of Rava.

אֶלָּא הָא כְּמַאן דְּאָמַר בַּעֲלֵי חַיִּים נִדְחִין, הָא כְּמַאן דְּאָמַר בַּעֲלֵי חַיִּים אֵינָן נִידְחִין.

Rather, Rava would claim that this matter depends on a dispute between tanna’im . This statement of Rava is in accordance with the opinion of the one who says that living creatures that become disqualified are permanently rejected from being sacrificed on the altar, and this animal was rejected when it was part of the mixture. That ruling of the mishna in Kinnim is in accordance with the opinion of the one who says that living creatures are not permanently rejected from the altar. Therefore, if the animal was sacrificed it is fit.

הֲרֵי שְׁחוּטִין – דִּלְכוּלֵּי עָלְמָא נִידְחִין;

The Gemara raises a difficulty: But there is the case of slaughtered offerings that are rejected from the altar, concerning which everyone agrees that these are rejected. Even those who say that living creatures generally are not rejected agree that, in this case, they should be rejected.