Reference for Chullin 115:7

אלא הא דתנן

But why did he not reply that the egg was of the first set? - Because if so it should have said 'it was finished' and not 'it developed'.<span class="x" onmousemove="('comment',' With regard to the eggs of the first set it should have used the term 'finished', for these commenced to form before the hen was rendered trefah. 'Developed' implies the entire forming and fashioning of the egg.');">⁶</span>

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