Reference for Chullin 55:1

מאי לאו בעוף דקא בעי ליה לדמיה ליניכא

Now presumably this statement refers to [the slaughtering of] a bird whose blood he would require for [destroying] the flax worm?<span class="x" onmousemove="('comment',' This clearly proves that birds must be ritually slaughtered by the law of the Torah; hence where they were not ritually slaughtered there would be no obligation to cover the blood and so it might be used for any purpose. tfk');">¹</span>

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