Why does the Torah write "Lo Ye'achlu" rather than "Lo Yochlu"?
Rashi: To implicate someone who feeds a Katan non-Kosher food. 1
Since it means 'it shall not be eaten through you' (Rashi).
Why can we not explain that it comes to forbid deriving benefit from non-Kosher food (as it usually does)?
Rashi: Because the Torah writes in Devarim (14:12) "Lo Yochlu", to preclude Isur Hana'ah.
Why does the Torah list the non-Kosher birds (here) but the Kosher animals (in Devarim 14:4 & 5)?
Rashi (in Re'ei): Because it always specifies the shortest list. 1
Ramban: It lists the non-Kosher birds and the eight rodents that are subject to Tum'ah (in Pasuk 29 & 30), because the list is comprehensive.
And the same applies to the list of Kosher animals in Re'ei.
What do all the forbidden birds have in common, that explains why the Torah forbids them specifically?
Ramban #1: Because all twenty-four birds in the list are Doreis 1 (they catch their prey and hold it down whilst they proceed to eat it alive), a clear indication that they are cruel, 2 and someone who eats them adopts their cruel nature. 3
Ramban #2 and Seforno (on Pasuk 4): Refer to 11:4:1:2.
Targum Yonasan: All birds that do not have an extra claw and a crop, whose gizzard (stomach) cannot be (easily) peeled is forbidden. 4
With the sole exception of either the Peres or the Ozniyah (two species of vulture), whose blood is nevertheless hot due to the hot climate of the areas in which it lives (Ramban).
It is this streak of cruelty that heats their blood, which in turn, directly enters the bloodstream of whoever eats them, causing him to become hot-blooded and cruel (Ramban).
In fact, the same reason applies to the prohibition against eating the forbidden species of animals, since all the animals that chew their cud and possess cloven hoofs are not Doreis