10 Beitzah 6b

Now, we know that food prepared, i.e., fit, for human consumption that became spoiled is not automatically considered prepared for dogs, as we learned in a mishna (see 2a): One may cut pumpkins before an animal to facilitate their consumption, and likewise one may cut up an animal carcass, even of an animal that died on Shabbat, before dogs. Rabbi Yehuda says: If the animal was not already a carcass, i.e., it was not dead and fit for dogs, prior to Shabbat, it is prohibited, because it is not in the category of items considered prepared for use on Shabbat. This shows that although this animal was fit for human consumption while alive, it does not automatically become prepared for dogs once it dies. If so, can food prepared for dogs be considered prepared for humans? He said to him: Yes. It is not surprising that something prepared and fit for humans is not considered fit and prepared for dogs, as that which is fit for a person, one does not throw it to dogs, and he has therefore removed that animal from his mind. However, something that is prepared for dogs is also considered fit and prepared for humans, as a person’s mind is on anything fit to be eaten by him. One does not completely remove from his mind even food meant for dogs, if it is kosher and edible. Consequently, one has in mind the possibility that he might eat the calf of a cow that is a tereifa once it is born, since at that point it will be kosher and edible. With regard to the dispute itself, the Gemara comments: It is taught in a baraita in accordance with the opinion of Rav; and it is taught in another baraita in accordance with the opinion of Shmuel, and some say in accordance with the opinion of Rabbi Yoḥanan. The Gemara elaborates: It is taught in a baraita in accordance with the opinion of Rav: A calf born on a Festival is permitted; a chick born on a Festival is prohibited. And what is the difference between this case and that one? This one, the calf, is prepared on account of its mother by slaughter; and that one, the chick, is not prepared on account of its mother. The Gemara further explains: It is taught in a baraita in accordance with the opinion of Shmuel, and some say it is the opinion of Rabbi Yoḥanan: A calf born on a Festival is permitted, and a chick born on a Festival is likewise permitted. What is the reason? This one, the calf, is prepared on account of its mother; and that one, the chick, is itself rendered permitted through slaughter. The Sages taught in a baraita: A chick born on a Festival is prohibited. Rabbi Eliezer ben Ya’akov says: Even on a weekday, the chick is prohibited on the day it hatched because its eyes have not yet opened. A small chick of this kind is not yet considered a bird fit for consumption; rather, it is similar to a creeping animal. The Gemara comments: In accordance with whose opinion is that which is taught: The verse that states: “Even all creeping animals that creep upon the earth, you shall not eat them, for they are a detestable thing” (Leviticus 11:42) comes to include in the list of prohibited creeping animals even chicks that have not yet opened their eyes. In accordance with whose opinion is this baraita? It is in accordance with the opinion of Rabbi Eliezer ben Ya’akov. § Rav Huna said that Rav said: An egg is fully formed upon its emergence; i.e., it is not considered an egg until it is laid. The Gemara inquires: What is the meaning of the statement: An egg is fully formed upon its emergence? To which issue is Rava referring? If we say he meant an egg is fully formed and called an egg only upon its emergence, and at this stage it is permitted to eat it with milk, this indicates that while an egg is still inside its mother, even if it is fully formed, it is considered meat and it is prohibited to eat it with milk. But isn’t it taught in a baraita: With regard to one who slaughters a chicken and finds fully formed eggs inside it, it is permitted to eat them with milk? Rather, Rav’s statement should be explained as follows: An egg is fully formed upon its emergence in that it is permitted to eat it on a Festival only if the entire egg emerged on a weekday. The Gemara expresses surprise at this claim: This indicates that if an egg is found inside its mother, it is prohibited to eat it on a Festival. But isn’t it taught: With regard to one who slaughters a chicken and finds fully formed eggs inside it, it is permitted to eat them on a Festival? And if you say: The baraita teaches us that which the mishna did not explicitly teach us, and Rav stated the halakha accordingly; however, this we already learned in the mishna here, as it says in the mishna: With regard to an egg laid on a Festival, Beit Shammai say it may be eaten, and Beit Hillel say it may not be eaten. And Beit Shammai and Beit Hillel disagree only with regard to an egg that was already laid, but concerning eggs inside their mothers, all agree that they are permitted. And if you say that the mishna should be explained in the opposite manner, as Beit Hillel also prohibit eggs inside their mothers, and the fact that the mishna teaches: Laid, is to convey the far-reaching nature of the opinion of Beit Shammai, that they permit even an egg that was laid. However, consider that which is taught in the aforementioned baraita: With regard to one who slaughters a chicken and finds inside it fully formed eggs, it is permitted to eat them on a Festival. In accordance with whose opinion is this baraita? It is the opinion neither of Beit Shammai nor of Beit Hillel. Rather, Rav certainly did not prohibit an egg that has not yet been laid. Instead, his statement should be explained as follows: An egg is fully formed upon its emergence, and it produces chicks, i.e., an egg laid in the regular manner can be incubated and a chick will hatch from it. By contrast, an egg that remained inside its mother cannot produce chicks. The Gemara asks: What is the practical halakhic difference of this observation? The Gemara answers: It is relevant for buying and selling. In other words, the difference between the types of eggs has ramifications for terms of commerce. This is like that incident involving a certain individual who would say to the general public: Eggs