Reference for Chullin 207:7
כל מילי דמימליך עליה שליח בר מיניה הוא
It follows however that he is forbidden the flesh of fowl, which is in accordance with R'Akiba's view, namely, that any variation concerning which the agent would ask for special instructions is deemed to be of the same species.<span class="x" onmousemove="('comment',' Anything which is not quite the same as the original thing requested but about which an agent would consider it proper to consult his principal is regarded as of the same species as the original thing requested; for were it not so, the agent would reject it immediately:without even consulting his principal. In the case of our Mishnah, if a person were to send another to buy flesh, the latter, if unable to obtain flesh of cattle, would certainly return and ask his principle whether or not he may buy fowls. Hence fowl is included in the term 'flesh'.');"><sup>3</sup></span>
Explore reference for Chullin 207:7. In-depth commentary and analysis from classical Jewish sources.