including the hide of the vulva, the halakha is the same: If one performs the sacrificial rites with intent to burn one of them outside its designated area, the offering is unfit, but there is no liability for karet for one who partakes of the offering. If he had intent to burn it beyond its designated time, this renders it piggul, and one is liable to receive karet for eating it. This baraita indicates that only Rabbi Shimon holds that the hide of the hooves is treated like its flesh, and that the Sages disagree, as Rabbi Yoḥanan stated.

MISHNA: And these are tereifot in a bird: One with a perforated gullet, or with a cut windpipe that was cut across its width; or if a weasel struck the bird on its head in a place that renders it a tereifa, as one must be concerned that the membrane of the brain was perforated; or if the gizzard was perforated; or if the small intestines were perforated. In a case where a bird fell into the fire and its innards were singed [neḥmeru], if they turned green they are unfit, and the bird is a tereifa, but if they are red the bird is kosher. If a person trampled the bird, or slammed it against a wall, or if an animal crushed it and it is twitching, it is a tereifa because its limbs were shattered. But if the bird lasted for a twenty-four-hour period, and then one slaughtered it, it is kosher.

GEMARA: The mishna states: If a weasel struck the bird on its head in a place that renders it a tereifa, one must be concerned that the membrane of the brain was perforated. Rav and Shmuel and Levi say: How does one inspect the membrane? After slaughter, one inserts his hand into the mouth of the bird and pushes the nerve tissue with his finger and inspects it. If the nerve tissue emerges and rises out through the hole in the skull, the animal is a tereifa, because this proves that the membrane has been perforated, allowing the nerve tissue through. And if not, the animal is kosher.

The Gemara asks: This works out well according to the one who says (45a) that an animal is not a tereifa unless the inner membrane is perforated as well. But according to the one who says that the animal is rendered a tereifa if the outer membrane was perforated, even if the inner membrane was not perforated, how can one rely on this inspection? Let us be concerned that perhaps the outer membrane was perforated but the inner membrane was not perforated, in which case the animal is a tereifa even if the nerve tissue does not emerge through the hole. The Gemara responds: If it is the case that the outer membrane was perforated, the inner membrane will inevitably burst due to its fragility, allowing the nerve tissue to emerge. If it does not emerge, it is certain that the outer membrane is intact as well.

Ze’eiri says: There is no effective inspection for a bird bitten on the head by a weasel, because the weasel’s teeth are so thin that even if they perforate the membrane, the nerve tissue will not emerge through the perforations. The Gemara asks: And if its teeth are thin, what of it? Certainly a small amount will emerge through the perforation. Rav Oshaya said: There is no inspection because its teeth are fine and crooked. The hole in the skull does not overlap the perforation in the membrane, and nothing will be able to escape.

The Gemara recounts: When Ze’eiri went up to Neharde’a, he sent a message to the Sages: The matters that I stated before you are an error on my part. In fact, they said this in the name of Rabbi Shimon ben Lakish: One inspects a bird bitten on the head by a weasel with one’s hand, pressing against the nerve tissue to see if it emerges through the hole, but not with a nail. One may not inspect it by dragging the tip of a nail over the surface of the membrane to see if it catches on a perforation, since the nail itself may perforate the membrane. And Rabbi Yoḥanan says: One may even inspect it with a nail.

The Gemara notes: And this disagreement is also reflected in the dispute of Rabbi Yehuda and Rabbi Neḥemya, wherein one inspected the bird by hand, and one inspected it with a needle. The one who inspected it by hand said to the one who inspected it with a needle: Until when will you waste the money of the Jewish people by causing them to discard kosher meat? Sometimes the needle itself will perforate a membrane that was initially whole. The one who inspected it with a needle said to the one who inspected it by hand: Until when will you feed carcasses to the Jewish people, as you permit for consumption a bird that might well be forbidden?

The Gemara asks: Carcasses? But this is a slaughtered animal; even if it is forbidden, it is a tereifa, not a carcass. Rather, he must have said: Until when will you feed tereifot to the Jewish people; perhaps the membrane of the brain was perforated. Inspection by hand is not reliable, since the teeth of the weasel are thin and crooked and the nerve tissue may not escape even if the membrane is perforated.

The Gemara notes: It may be concluded that it is Rabbi Yehuda who inspected it by hand, as it is taught in a baraita: Rabbi Shimon ben Elazar says in the name of Rabbi Yehuda that one may inspect a bird bitten on the head by a weasel with one’s hand, but not with a nail. The baraita continues: If the bone of the skull was broken, even if the membrane of the brain was not perforated, the animal is a tereifa. The Gemara affirms: Indeed, it may be concluded that Rabbi Yehuda permits inspection only by hand.

The Gemara objects: This itself is difficult. You said in the baraita: One may inspect a bird injured by a weasel with one’s hand, but not with a nail; apparently, it has an option of inspection. But you then teach: If the bone of the skull was broken, even if the membrane of the brain was not perforated, the animal is a tereifa; apparently it has no inspection, because inspecting for a perforation would be pointless. The Gemara responds: In the latter clause, we come to discuss a water bird, which cannot be inspected, since it has no membrane. The Gemara clarifies: Can it enter your mind that it has no membrane? One can see that it does. Rather, the response is: Since its membrane is fragile, it must have ruptured when the skull was broken.

Similarly, the Gemara relates that Rav Naḥman said to Rav Anan: The Master says that Shmuel inspects a bird bitten on the head by a weasel with his hand and deems it kosher if the membrane is not perforated, and our colleague Rav Huna also says that Rav inspects it by hand and deems it kosher. But doesn’t Levi teach: Those tereifot that the Sages enumerated in an animal apply likewise in a bird, and in addition to those, a bird is a tereifa if the bone of the skull was broken, even if the membrane of the brain was not perforated? If so, how can a bird be permitted through inspection? Rav Anan said to him: That baraita is referring to a water bird, which cannot be inspected since it has no membrane. The Gemara clarifies: Can it enter your mind that it has no membrane? Rather, the response is: Since its membrane is fragile.

Similarly, the Gemara relates: There was a certain hen that was in the house of Rav Ḥana whose skull was injured. He sent it before Rav Mattana, who inspected it and found that the bone of the skull was broken but the membrane of the brain was not perforated, and he deemed it kosher. Rav Ḥana said to Rav Mattana: But doesn’t Levi teach: Those tereifot that the Sages enumerated in an animal hold likewise in a bird, and in addition to those, a bird is a tereifa if the bone of the skull was broken, even if the membrane of the brain was not perforated? Rav Mattana said to him: That baraita is referring to a water bird, which cannot be inspected since it has no membrane. The Gemara clarifies: Can it enter your mind that it has no membrane? Rather, say that his response was: Since its membrane is fragile.

The Gemara notes that Rav Sheizvi would inspect the membrane of the brain by the light of the sun. Rav Yeimar would inspect it by pouring water into the skull through the hole, to see if it emerges mixed with nerve tissue. Rav Aḥa bar Ya’akov would inspect it