2,545. A Missing or Extra Organ
Hilchos Shechita 6:19
The spleen isn’t one of the organs that disqualifies through even the smallest hole. A disqualifying hole in the spleen has an inconsistent measure, as follows: one end of the spleen is thick and the other is thin, like a tongue. If the thick end was punctured by a hole that goes from one side to the other, the animal is a treifa. If the hole doesn’t go from one side to the other, then if a piece as thick as a gold dinar (a denomination of coin) remains, the animal is still permitted. Smaller than that, it’s considered as if the hole goes from one side to the other, with the result that the animal is a treifa. If the thin side of the spleen is punctured, the animal is still kosher.
Hilchos Shechita 6:20
Regarding all the organs about which the Sages said that even the smallest hole makes an animal a treifa, if the organ is removed – whether by illness or manually, or the animal was born without it – in all of these cases, the animal’s a treifa. The same is true if the animal was born with two of that organ because the rule for an extra limb or organ is the same as for when it’s missing. Accordingly, if an animal or bird is missing part of its digestive system, its gall bladder or some comparable organ, it’s a treifa. Likewise, if an animal or bird is found to have two of one of these organs, it’s a treifa. However, if the spleen was removed or if the animal had two, then it remains permitted, because the spleen isn’t one of the organs of this type.