akuperma: Wrong. That’s not what veal is. And according to the Rama there is no way for veal to be Kosher.
DY: Many major Poskim, including R’ Schachter (who will end up being the Posek for this community), hold that we can rely on the Teimani Mesorah.
nisht: Swordfish has absolutely nothing to do with this, nor the concept. There is no one who holds you need a Mesorah on fish. Just find a scale and eat. Swordfish is a discussion because of the nature of their scales, nothing else.
L’ma’aseh, we only need a Mesorah on birds, not animals, because all Kosher animals will cross-breed which trumps the lack of a Mesorah. They have yet to find an animal with the Simanim that can’t cross-breed and create viable offspring with another Kosher animal as far as I know. (Also, far more Rishonim hold you need a Mesorah by birds than animals.)
Turkeys are a fascinating Shailah and historical case. If they’re Muttar, it’s not because they’re related to chickens. It’s because the Simanim are identical. (Though if one reads the Gemara and the Rambam they should be Assur for everyone; even Sefardim agree you need a Mesorah on new-world birds.)