Mishnah Parah 2:1: Rabbi Eliezer says: A pregnant red heifer is valid [for the ritual]. And the Sages invalidate it. Rabbi Eliezer says: It cannot be purchased from gentiles. And the Sages validate [purchasing a red heifer from gentiles]. And furthermore all communal and individual sacrifices [may] come either from the Land [of Israel] or from outside of the Land, either from the new [grain, harvested in the new year but before the omer sacrifice is brought on Pesach, and forbidden until after the sacrifice] or from the old [grain], except for the omer and the two loaves [offered on Shavuot] which may only be brought from the new [grain] and from the Land.

רַבִּי אֱלִיעֶזֶר אוֹמֵר, פָּרַת חַטָּאת הַמְעֻבֶּרֶת, כְּשֵׁרָה. וַחֲכָמִים פּוֹסְלִין. רַבִּי אֱלִיעֶזֶר אוֹמֵר, אֵינָהּ נִלְקַחַת מִן הַנָּכְרִים. וַחֲכָמִים מַכְשִׁירִים. וְלֹא זוֹ בִלְבַד, אֶלָּא כָל קָרְבְּנוֹת הַצִּבּוּר וְהַיָּחִיד בָּאִין מֵהָאָרֶץ וּמִחוּץ לָאָרֶץ, מִן הֶחָדָשׁ וּמִן הַיָּשָׁן, חוּץ מִן הָעֹמֶר וּשְׁתֵּי הַלֶּחֶם שֶׁאֵינָן בָּאִין אֶלָּא מִן הֶחָדָשׁ וּמִן הָאָרֶץ:

Mishnah Parah 2:2: A [red] heifer whose horns and hoofs are black, they [the horns and hoofs] should be removed. The eyeball, the teeth and the tongue do not invalidate it [from being entirely red, if they are black]. The runt is valid. [If] it had a boil which was cut off, Rabbi Yehudah invalidates it; Rabbi Shimon says: Any time a removal occurred and red hair did not grow in its place is invalid.

פָּרָה שֶׁקַּרְנֶיהָ וּטְלָפֶיהָ שְׁחוֹרִים, יָגֹד. גַּלְגַּל הָעַיִן וְהַשִּׁנַּיִם וְהַלָּשׁוֹן אֵינָם פּוֹסְלִים בַּפָּרָה. וְהַנַּנֶּסֶת, כְּשֵׁרָה. הָיְתָה בָהּ יַבֶּלֶת וַחֲתָכָהּ, רַבִּי יְהוּדָה פוֹסֵל. רַבִּי שִׁמְעוֹן אוֹמֵר, כָּל מְקוֹם שֶׁנִּטַּל וְלֹא הֶעֱלָה מְקוֹמוֹ שֵׂעָר אָדֹם, פְּסוּלָה: