• Shechitah requires most of two סימנים of an animal, and most of one סימן of a bird

The second Perek begins: השוחט אחד בעוף ושנים בבהמה שחיטתו כשרה – if one shechts one pipe of a bird or both pipes of an animal, his shechitah is valid, ורובו של אחד כמוהו – and cutting most of one pipe is like cutting all of it. Rebbe Yehudah requires cutting the וורידין (the main blood vessels of the neck), and the Gemara will explain this to refer to shechitah of birds. If one shechted half of one סימן of a bird, or one and a half סימנים of an animal, the shechitah is invalid. The Mishnah’s term "השוחט" implies that its shechitah is only valid בדיעבד. But how can shechitah of two סימנים of an animal be בדיעבד? What more should he cut? The Gemara answers that the Mishnah’s expression refers to shechting one סימן of a bird, indicating that לכתחלה, one should shecht both סימנים of a bird. Alternatively, the Mishnah’s expression refers to shechting most of a סימן, indicating that לכתחלה, one should shecht the entire סימן.

• מנין לשחיטה שהיא מן הצואר

Rav Kahana asked: מנין לשחיטה שהיא מן הצואר – from where do we derive that shechitah means cutting from an animal’s throat? He suggests the passuk: "ושחט" את בן הבקר – and he shall slaughter the bull, which teaches: ממקום ששח חטהו – from the place where [the animal] bends, cleanse it by removing its blood. However, the Gemara objects that perhaps it refers to cutting its tail, which is bent, or its ear, which it can bend!? Although we require releasing דם הנפש – lifeblood, perhaps one should cut from the ear until reaching the דם הנפש!? Furthermore, from where do we derive the various acts which invalidate shechitah, such as שהייה – pausing!? Rather, these disqualifications must be גמרא – known by oral tradition, and the requirement to shecht from the throat was similarly passed down by tradition.

Similar objections are posed to other suggested sources for shechting from the throat, with the same conclusion. Rebbe Chiya provides another source: the Torah instructs to arrange all the parts of a korban on the מזבח for burning, and specifically mentions arranging the head. The reason is that the head uniquely was not skinned, שכבר הותז – because it was already severed during shechitah. This proves shechitah is from the throat.

• Fish do not require shechitah

Bar Kappara taught a Baraisa which notes that הטיל הכתוב לעוף בין בהמה לדגים – the Torah placed “bird” between “animal” and “fish” in the opening passuk of the laws of kosher animals. Thus, a bird cannot require shechting two סימנים, since it is also compared to fish; it cannot be exempt entirely from shechitah (like fish), since it is also compared to animals. Therefore, we must conclude that birds require the shechitah of one סימן. Fish do not require shechitah, because a passuk which mentions the shechitah of cattle says about fish "יאסף" – will be gathered, implying that they require nothing more than being caught. A traveling Galilean once darshened: an animal, which was created from the dry land, requires shechitah of both סימנים. Fish, which were created from the water, do not require any shechitah. A bird, שנברא מן הרקק – which was created from mud (a combination of earth and water), requires shechitah of one סימן. Rav Shmuel of Kaputkiyah brought support for the fact that birds were created from mud, which includes water: שהרי עופות יש להן קשקשת ברגליהם כדגים – because birds have scales on their feet, similar to the scales of fish.