Wikipedia's article on R' Dr. Bernard (Yissochor Dov) Illowy cites this article, which says that "It’s the muscovy duck that’s highly controversial, due to its ban in America by the ascerbic Rabbi Bernard Illowy in the mid 1800’s."

Why would the muscovy duck be treif and what is the source for R' Illowy's assertion?

1 Answer 1


The kosher status of birds differs from that of animals and fish, in that there are no biblically based physical indicators and thus today the determination is made based on tradition (mesorah). Rabbi Illoway, upon seeing the muscovy in New Orleans, determined it was a novel species for which he was unable to find a reliable tradition. With the support of Rabbi Samson Raphael Hirsch and Rabbi Nathan Adler, he therefore declared it nonkosher. further details can be found in this article on the subject: http://www.kashrut.com/articles/ThreeBirds/

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    Ari Zivotofsky, welcome to Mi Yodeya, and thanks very much for the informative answer and link! I hope you'll look around the site and find other information of interest, perhaps among our collection of unanswered Kashrut questions.
    – Isaac Moses
    May 2, 2017 at 20:48
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    Are you the same Ari Zivotofsky as the one mentioned in the article in the OP? May 2, 2017 at 20:52
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    @NoachMiFrankfurt Yes, he is. I emailed R' Dr. Zivotofsky and Dr. Greenspan, the owners of the site you linked to, to ask if either of them could post an answer here, and R' Dr. Zivotofsky promptly posted this.
    – Isaac Moses
    May 2, 2017 at 20:56
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    One important element mentioned from Rabbi Zivotofsky's article concerning the ban from Rabbi Illoway, Hirsch and Adler was that Rabbi Illoway misidentified the type of egg from Muscovy ducks. He said they are green and round on both ends. That is not correct. They are round on one end and pointed on the other. So the contention of a definite sign from a non-kosher species doesn't exist. May 2, 2017 at 22:41
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    The linked article you wrote was fascinating and clearly written so that even a layman can understand. Yasher koach!
    – Mike
    May 3, 2017 at 3:01

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