What do we learn from the word "Min [ha'Of]")?
See Rashi, 22:19.
Moshav Zekenim (2): Big blemishes disqualify, e.g. its wing dried, its eye was blinded, or it became Tereifah. On verse 14, he says that it is only if its eye was removed, but not if it was blinded; only for freeing a slave, "Yeshalchenu" includes this. However, he also brings from Zevachim 35b that the only Mum allowed is cataracts in the eye. He also asks why [Sifra] mentions 'its wing dried or its foot was cut off', and not vice-versa.
Why does the Torah insert the word "Bnei" regarding "Yonah" but not regarding "Torim" (turtledoves)?
Rashi and Targum Yonasan: To teach us that, whereas a Tor is only eligible to be brought as an Olah when it is mature, a dove is eligible only when it is still young. 1
What do we learn from the two times "Min" ("Min ha'Torim u'Min b'nei ha'Yonah")?
Rashi: They come to disqualify both birds when their feathers have begun to turn yellow, the former because they are not yet classified as mature, the latter, because they are no longer considered young.
Why did the Torah render eligible as a Korban specifically these two types of bird?
Ramban #1: They are readily available and easy to catch. 1
Ramban #2, Moshav Zekenim: Because of the grown-up Tor's fidelity to its mate - once it has chosen its mate, it will never exchange it for another, or even take another mate after it dies - Likewise, Yisrael never exchange Hashem for another G-d. Young doves are extremely attached to their nests with bonds of love - more than any other bird. Moreover, unlike other birds, which flee their nests the moment someone touches them to take its chicks, doves remain in their nests - Likewise Yisrael never forsake their Creator and His Torah. A Yisrael will submit to be hung rather than give up his religion (Midrash Rabah)!
Moshav Zekenim citing R. Eliezer of Garmaiza: Torim are pursued more than other birds, like Yisrael are pursued. They never switch mates, even after its mate dies; doves switch after death, therefore only young doves may be offered. Yisrael are compared to a dove, which never switches its mate, i.e. in its mate's lifetime.
Moshav Zekenim: When Yisrael sin, they are compared to birds
Ramban, Moshav Zekenim: As the Midrash Rabah writes in connection with a lamb and a kid-goat - which the Torah renders eligible as a Korban, to exempt one from having to take one's bow and arrow and going to hunt Chayos. The Torah did not allow chickens, because they are promiscuous.
Why must one take specifically grown-up Torin and young doves?
Ramban #1: Refer to 1:14:4:2. Also, adult doves are exceptionally jealous by nature, and in their jealousy, they leave their current mates and take different mates.
Ramban (citing Moreh Nevuchim): Because mature doves and young Torim are more tasty that their counterparts. 1
Ramban #2: Because mature doves sharpen one's intellect, whereas young Torim are good for those whose limbs no longer function well.
See Ramban, who rejects that reason.
Why did the Torah not include chickens?
Ramban: Because they are promiscuous.
Rashi writes that "Min" disqualified a bird missing a limb. This is forbidden even for Bnei Noach. Why did the Torah need to write this?
Riva:, It forbids even if the limb is still there, e.g. its eye was sunken but did not leave, or its wing 1 dried.
Riva citing R. Tam of Orlins, Moshav Zekenim citing R. Yeshayah; If not for "Min ha'Of", I would say that missing a limb is disqualified for Bnei Yisrael, but not for Bnei Noach. We say that anything written about Bnei Noach that was not repeated at Sinai (after Matan Torah), it applies to Yisrael, but not to Bnei Noach.
Moshav Zekenim citing Ri: Before Matan Torah, one could offer all [Tahor] animals and birds, except for Mechusar Ever. At Matan Torah, the Torah disqualified animals with a Mum. One might have thought that the Halachah changed; from now and onwards, birds are allowed even Mechusar Ever.
It seems that 'Gufo' is a printing mistake; it should say 'Gapo' (PF).