Gemara

(Mishnah): If one slaughters on Shabbos, even though he is Chayav Misah, the Shechitah is Kosher.

(Rav): The meat may not be eaten that same day.

(Rabanan): (He holds that) the Mishnah is like R. Yehudah (but R. Meir permits eating it the same day).

15a: R. Meir permits an animal slaughtered on Shabbos only when one (in the household) was (dangerously) sick when Shabbos began. (They planned to slaughter for him if necessary.)

Question: If so, it was permitted to slaughter. Why does R. Yehudah forbid the meat?

Answer: The case is, he became Bari (healthy) again before the Shechitah; like Rav Acha taught.

(Rav Acha bar Rav Ada bar Ahavah citing Rav): If one slaughters (on Shabbos) for a Choleh (sick person), a Bari may not eat from the meat. If one cooks for a Choleh, a Bari may eat the food.

Question: Why are these different?

Answer: One could not eat the meat without Shechitah. One could have eaten the food raw.

(Rav Papa): Sometimes one slaughters for a Choleh and a Bari may eat from the meat, e.g. someone was sick when Shabbos began;

Sometimes one cooks for a Choleh and a Bari may not eat the food, e.g. he cut gourds.

(Rav Dimi of Nehardai): The Halachah is, if one slaughters for a Choleh, a Bari may eat from the meat raw.

Since one must slaughter to eat even a k'Zayis, there is no concern lest he slaughters also for the sake of a Bari.

If one cooks for a Choleh, a Bari may not eat the food.

This is a decree, lest he come to cook extra for a Bari.

Beitzah 2b (Rabah): The Mishnah forbids an egg laid on Yom Tov (or Shabbos), even if the hen was destined to be eaten. This is because it is prepared a day before it is laid, and sometimes this is on Shabbos.

Question: If so, we should permit an egg laid on Shabbos (that is not after Yom Tov)!

6b: Something prepared for man is not considered prepared for animals;

(Mishnah): We may cut a gourd for an animal to eat, or a Neveilah for a dog to eat;

R. Yehudah says, if it was not a Neveilah from before Shabbos, it is forbidden, for it was not prepared.

Rishonim

Rif and Rosh (4a and 1:20): The Halachah is, if one slaughters for a Choleh, a Bari may eat from the meat raw. If one cooks for a Choleh, a Bari may not eat the food. This is a decree, lest he come to cook extra for a Bari.

Rosh: The Rif omitted Rav's teaching that if one slaughters for a Choleh, a Bari may not eat from the meat, but if one cooks for a Choleh, a Bari may eat the food. This is because it is not the Halachah. It discusses one who became sick on Shabbos. The animal is forbidden due to Muktzeh. We hold like R. Shimon. He permits all Muktzeh due to Isur except for a lamp burning on Shabbos, for there he was Docheh b'Yadayim (did an act, i.e. lit it before Shabbos, that prevents him from using it), figs and raisins (put on the roof to dry out; they are not proper to eat when they are partially dry), and similar cases.

Rambam (Hilchos Shabbos 2:9): If one slaughtered on Shabbos for a Choleh, one (a Bari) may eat the meat raw.

Ra'avad: This is if he was sick from before Shabbos.

Magid Mishneh: Since we hold like R. Shimon, the only Muktzeh due to Isur is when he was Docheh b'Yadayim. If not, it is permitted. Even though the animal was Muktzeh due to the Isur to slaughter it, he was not Docheh b'Yadayim.

Ran (Shabbos 17a DH Garsinan): If one slaughtered on Shabbos for a Choleh, a Bari may eat the meat raw. This is if he was sick from before Shabbos. If he became sick on Shabbos, a Bari may not eat it, for it was Muktzeh from before Shabbos. This is clear from Chulin. The Rif wrote Stam. He did not explain this enough.

Beis Yosef (OC 318 DH Aval): It seems that the Ran holds that Rav Dimi argues with Rav and Rav Papa only regarding cooking meat slaughtered before Shabbos for a Choleh who became sick today. Rav Dimi decrees to forbid even this, lest one cook extra for a Bari. All permit meat slaughtered on Shabbos to a Bari only if the Choleh was sick from before Shabbos. If not, it is Muktzeh. Rashi explains like this. The Rosh and Magid Mishneh hold that Rav Dimi argues also about Shechitah. He permits in every case, even if he became sick today. Alternatively, they agree that Rav Dimi argues only about cooking. Also he permits what is slaughtered only if he was sick from before Shabbos, like Rashi says. They hold that since the Gemara said Stam 'if one slaughtered for a Choleh, it is permitted for a Bari', this is even if he became sick today, for we hold like R. Shimon, who forbids Muktzeh only if he was Docheh b'Yadayim.

Beis Yosef (DH v'Yesh): Why didn't the Ran notice what the Rosh and Magid Mishneh wrote? Rashi (Shabbos 45b) says that R. Shimon forbids dry figs and raisins because he was Docheh b'Yadayim, and they are not proper (now). One was not Docheh the animal b'Yadayim. Why is it Muktzeh? Perhaps he equates this to something attached to the ground. Even though he was not Docheh b'Yadayim, it is forbidden, like we say in Beitzah (24b). Rashi says that even R. Shimon agrees. Since he did not detach it from before Shabbos, he diverted his mind from it. It is like dry figs and raisins. Here, since he did not slaughter it from before Shabbos, he diverted his mind from it. The Ba'al ha'Ma'or (Shabbos 13a DH v'Ha) says that Rashi did not need to say this, for R. Shimon agrees about all Muktzeh due to Isur that one has no intent to use, such as a cup, bowl or glass goblet (kinds of lamps). If one checked a Bechor (on Yom Tov and found that it has a blemish), R. Shimon forbids slaughtering it on Yom Tov, for he forbids checking Mumim on Yom Tov. The Ramban disagreed, but the Ran sided with the Ba'al ha'Ma'or. Without Rashi's reason, we can say that an animal is Muktzeh if the Choleh became sick today. The Rashba says that some say that even R. Shimon, who permits Muktzeh due to Isur, admits regarding Shechitah. Even Mar brei d'Rav Yosef (Beitzah 27b), who says that R. Shimon permits animals that died (on Shabbos), admits here. Animals often die, so one waits for his animal will die. One does not wait for his animal to be slaughtered. My Rebbi (R. Yonah) says that R. Shimon forbids Muktzeh due to Isur only if he was Docheh b'Yadayim and he does not wait for it to become permitted.

Beis Yosef (DH ha'Shochet): Rashi explains that even though there is no Isur Shabbos when one slaughters for a Choleh, since Piku'ach Nefesh overrides Shabbos, the food is Muktzeh, since Bein ha'Shemashos it was Muktzeh, since he was not sick then. The animal was not destined to be slaughtered on Shabbos.

Poskim

Shulchan Aruch (OC 318:2): If one slaughtered on Shabbos for a Choleh, whether he was sick from before Shabbos, or he fell sick on Shabbos, a Bari may eat it raw (on Shabbos).

Taz (2): The Beis Yosef permits even if he became sick today. He brings from the Rosh that we hold like R. Shimon, who permits all Muktzeh due to Isur except for a lamp burning on Shabbos, for he was Docheh b'Yadayim and diverted his mind from it. He said that the Rambam and Magid Mishneh agree. The Ra'avad and Ran disagree. They hold that even R. Shimon forbids. This is difficult. In Siman 310, the Beis Yosef wrote that R. Shimon agrees about something without a permitted use. Why does he permit an animal? We must say that since it became permitted and usable on Shabbos, the Isur went away. This is difficult, we do not rule like R. Shimon regarding this! We forbid a lamp that was lit on Shabbos and extinguished (OC 279)! Do not say that in Siman 310, the Beis Yosef teaches according to the Ra'avad and Ran. He was explaining how we rule! He asked why the Ran overlooked that the Halachah follows R. Shimon. He should have challenged those who permit! It seems that we do not rule like R. Shimon regarding an Isur that became permitted and usable on Shabbos, for since it was forbidden at the beginning of Shabbos, it is forbidden for all of Shabbos. This is when the Heter comes due to a change in the Isur. E.g. if a lamp was burning Bein ha'Shemashos, even if it extinguished, we consider it as if it is still burning. We ignore the change. If Sukah decorations fell, since they were hanging in the Sukah Bein ha'Shemashos, it is as if they are still hanging. If coins were on a pillow, we consider it as if they are still on it. An animal slaughtered for a Choleh did not change. The change is due to the Choleh. Had he been sick Bein ha'Shemashos, the animal would have been permitted then. It would not be Muktzeh at all. In such cases, we do not forbid for all of Shabbos because it was forbidden Bein ha'Shemashos. The only problem is if the person diverted his mind from it for all of Shabbos. Regarding this, we hold like R. Shimon, who permits Muktzeh. Even though I did not see anyone who explicitly says so, and the Ra'avad and Ran disagree, the Rambam and Rosh hold like I said.

Gra (DH Bein): The Shulchan Aruch is like the conclusion (in Chulin), which is unlike what was said above, that R. Meir permits only when he was sick from before Shabbos. Rather, it is permitted in every case (for he was not Docheh b'Yadayim). Also Beitzah 6b holds like this. Tosfos (6b DH Hashta) did not understand this, therefore he had great difficulty explaining why an animal that died on Shabbos is called prepared for man. The Rashba brings from R. Yonah that Beitzah 6b argues with Chulin 15a. The latter Sugya connotes that even R. Shimon agrees (a forbids an animal slaughtered on Shabbos). One waits for his animal to die, but not for it to be slaughtered. In Beitzah, even R. Yehudah considers an animal prepared for man. Also on 2b, the Gemara asked that we should permit an egg laid on Shabbos, even though the mother was designated to be eaten and is Muktzeh due to the Isur to slaughter. Even if you will say that the Gemara asked according to the Halachah, i.e. R. Shimon, in any case we learn that the Halachah follows R. Shimon regarding this. Rashi, Tosfos and the Ramban permit only if he was sick from before Shabbos. The Rif and Rambam connote like R. Yonah and the Rosh, who permit in every case.

Kaf ha'Chayim (24): The Maharshal (1:30) forbids if he became sick today.

Mishnah Berurah (9): There is no concern lest they do extra for a Bari, for one must slaughter even for a k'Zayis.

Kaf ha'Chayim (328:87): If a small chicken suffices, they may not slaughter a big one. However, if they brought a chicken to a Shochet, he need not investigate if there is a smaller one that would suffice. They ones who bring to him should check this.