(Mishnah): As long as Chametz may be eaten, one may feed it to his domestic and wild animals and birds, sell it to a gentile and derive benefit from it. When its (permitted) time expires, it is prohibited to derive benefit from it.

(After the time) one may not fuel his oven or stove with it.

R' Yehudah says one may only destroy Chametz through burning.

The Chachamim say that one may crumble it and throw into the wind or drop it into the ocean.

(Gemara - R' Imi): R' Meir is the tanna who holds that as long as Chametz may be eaten, it may be fed; but once it is prohibited to eat, it is prohibited to feed. However, according to R' Yehudah, in the 5th hour, even though it is prohibited to eat, it may be fed.

Question (R' Aba): The Mishnah (in the 3rd Perek) says, 'Sei'or (partially fermented dough) must be burned; one who eats it is exempt'. And Rav Huna quoted Rebbi saying that it is permitted to feed it to dogs, (hence we find that sei'or may not be eaten but may be fed)?!

Answer (R' Yosa): Did the tanna come to teach that [anything that is prohibited to eat is prohibited to feed]? Rather, he came to teach about times (that as long as Chametz may be eaten, it may be fed. This is certainly the opinion of R' Meir, not R'Yehudah. However, sei'or does not depend on time, as even on Pesach itself it may not be eaten but it may be fed.)

(R' Bun bar Chiya to R' Zeira): Our Mishnah said that one can drop Chametz into the ocean even though it is eaten by fish - this proves that it is permitted to feed Chametz to hefker (ownerless) animals.

Question (R' Yirmiyah): The Mishnah said 'crumble it'. (if it would be permitted to feed hefker animals, the Mishnah would have allowed throwing whole loaves into the ocean)?

Answer (R' Yosa): The Mishnah only required partially crumbling it in order to annul it and show that he does not want it anymore, but it did not require making it into crumbs to make it inedible.

Question: What is the source that one may not feed a hefker animal?

Answer: (Shemos 13,3) "Chametz shall not be eaten'' - today, even by your dogs [this comes to prohibit deriving benefit from Chametz] (Note: These words are taken out by the Tur and Korban ha'Edah).

Question: What are we dealing with here? If the Torah is prohibiting giving to one's dog, it is the prohibition to gain benefit from Chametz that is learned from "lo sochal Chametz''?!

Conclusion: Rather it is referring to feeding other people's dogs. We can therefore conclude that one may not feed Chametz to hefker animals.