Reference for Chullin 89:2

אמר רב יהודה אמר רב

Rab Judah said in the name of Rab: If the windpipe was perforated [with many holes] like a sieve, they are reckoned together in order to make up the greater part.<span class="x" onmousemove="('comment',' I.e., the holes are considered as being adjacent and in a line, and if then it appears that the greater portion of the circumference of the windpipe is severed the animal is trefah.');">¹</span>

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