Reference for Keritot 41:5

אי מה בהמה שאינה באם על הבנים אף עוף שאינו באם על הבנים

so should be included only those animals that are not subject to kil'ayim;<span class="x" onmousemove="('comment',' I.e., cattle and goat, whose hair, too, is not subject to that law. Sheep would be excluded, for its wool is subject to the law of kil'ayim.');">⁵</span>

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