Reference for Chullin 115:2

איתיביה רב אשי לאמימר

but the subsequent ones are permitted, for they are the product of two causes.<span class="x" onmousemove="('comment',' The egg is the product of the hen which is forbidden and the cock which is permitted; and it is held that the product of two causes, one of which is prohibited and the other permitted, is permitted. ihuau');">²</span>

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