A Law Most Fowl: Why can't we eat chicken with milk?

(21) You shall not eat anything that has died a natural death; give it to the stranger in your community to eat, or you may sell it to a foreigner. For you are a people consecrated to the Lord your God. You shall not boil a kid in its mother's milk.

(1) All meat is forbidden to cook with milk, except for the meat of fish and locusts. And it is forbidden to place it with cheese on the table, except for the meat of fish and locusts. One who vows [to abstain] from meat, is permitted to [eat] fish and locusts. "A bird may go on with cheese on the table, but is not eaten," in the words of Beit Shammai. And Beit Hillel says, "It does not go and it is not eaten." Said Rabbi Yose, "This is [one] of the lenient rulings of Beit Shammai and stringent rulings of Beit Hillel." About which table were they speaking? About a table on which one eats. But for a table where one sets dishes on it, one puts this next to this and does not worry.

(4) [A mixture of] the meat of a permitted animal with the milk of a permitted animal is forbidden to cook and forbidden from benefit. [A mixture of] the meat of a permitted animal with the milk of a prohibited animal, [or] [a mixture] of the meat of a prohibited animal with the milk of a permitted animal is permissible to cook and permissible for benefit. Rabbi Akiva says, "Wild animals and birds are not [forbidden in mixtures with milk] from the Torah, as it says, 'You may not cook a kid in its mother's milk,' three times. It exempts the wild animal, the bird, and the prohibited domesticated animal." Rabbi Yose HaGelili says, "It is stated, 'You may not eat any nevelah[an improperly slaughtered animal of a permitted species],' (Deuteronomy 14:21) and it is stated, 'You may not cook a kid in its mother's milk,' (Ibid.). That which [may become] forbidden as nevelah is forbidden to cook with milk. A bird, which [may become] forbidden as a nevelah, one might think that it should be forbidden to cook with milk, [but] the Torah says, "In its mother's milk." This excludes a bird, which does not have mother's milk.

Rabbi Yose HaGelili says, "It is stated, 'You may not eat etc.'" What is the difference between the views of R. Jose the Galilean and R. Akiba? ... You may Say, the difference between them is as regards fowls: R. Akiba maintains that wild animals and fowls are not included in the prohibition of the Torah but are prohibited Rabbinically, whereas R. Jose the Galilean maintains that fowls are not even prohibited by the Rabbis ... In the place of R. Jose the Galilean they used to eat fowl's flesh cooked in milk.

Agra, the father-in-law of R. Abba, recited: A fowl and cheese may be eaten without restriction. He recited it and he himself explained it thus: it means without washing the hands or cleaning the mouth [between the eating of the one and the other].

R. Isaac the son of R. Mesharsheya once visited the house of R. Ashi. He was served with cheese which he ate and then was served with meat which he also ate without washing his hands [between the courses]. They said to him: Has not Agra the father-in-law of R. Abba recited that a fowl and cheese may be eaten without restriction? A fowl and cheese, yes; but meat and cheese, no! — He replied: That is the rule only at night, but by day I can see [that my hands are clean].

(4) Similarly, the meat of a wild beast and the meat of a fowl together with the milk of a wild beast or the milk of a domesticated animal is not forbidden according to Scriptural Law. Therefore it is permitted to cook it and it is permitted to benefit from it. It is forbidden to partake of it according to Rabbinic Law so that people at large will not be negligent and come to violate the Scriptural prohibition against milk and meat and partake of the meat of a kosher domesticated animal [cooked] in the milk of a kosher domesticated animal. For the literal meaning of the verse implies only the meat of a kid in the milk of its actual mother. Therefore, they forbade all meat in milk.