Reference for Shabbat 310:9
אמר רב אשי מתניתין נמי דיקא אין נותנין מים לפני דבורים ולפני יונים שבשובך אבל נותנין לפני אווזין ולפני תרנגולין ולפני יוני הרדיסיות מ"ט לאו משום דהני מזונותן עליך והני אין מזונותן עליך
Hence mehalkitin is surely [forcing food] so far down that it cannot return, while malkitin is [only] so far that it can return. From this it follows that hamra'ah means [stuffing] with a utensil, which refutes Rab Judah?<span class="x" onmousemove="('comment',' For the Mishnah employs mehalkitin in respect of fowls and mal'itin i.e., hal'atah in respect of calves as parallel terms, and both are permissible. Hence hamra'ah, which is forbidden, must refer to feeding with a utensil. ');"><sup>16</sup></span> — Rab Judah can answer you: In truth mehalkitin means feeding by hand, while malkitin means casting [the food] before them, but as to your difficulty, Is it then not even permitted to cast [food] before the doves of the dove-cote and of the loft, [that indeed is so, for] you are responsible for the food of the former [sc. fowls], but not for that of the latter.<span class="x" onmousemove="('comment',' Because doves can fly about in the fields and find their own food. ');"><sup>17</sup></span>