Yosef Karo, Shulchan Aruch, Yoreh Deah — 82…
“ If it's hardened and attached, and he puts it in the sun and it softens and gets peeled by hand, behold it's a sign of purity. And even though it has these three signs, it should not be eaten, because we are concerned lest it's a bird of prey, rather, unless they have a tradition that was transmitted to them by their ancestors that it is kosher. (words of Rambam, Forbidden Foods 1:18) .3 Some say any bird whose beak (chartum) is wide and the palm of its foot is wide like a duck, it's definitely not a raptor (dores) , and is permitted to eat if it has the three signs on its body. ”
