Reference for Chullin 204:3

הכא נמי

[If he ate] an unclean bird, whether alive or dead, however small it was, [he is liable].<span class="x" onmousemove="('comment',' Because it is a complete entity expressly prohibited by the Torah, and one is liable for it no matter how small it is. Cf. Mak. 13a.');"><sup>3</sup></span>