There is a prohibition of throwing out bread in larger quantities than a k'zayit (olive-size) if it is still fit for human consumption (see Orach Chayim 180:3; Regarding if it is no longer fit for human consumption, see Beis Baruch on Chayei Adam 45:22, cited here). Similarly, one is not supposed to feed bread fit for human consumption to animals or birds. If one knows the bread will not be eaten, according to Rav Y.S. Elyashiv and Rav Y.Y. Fisher (oral ruling quoted in V'zos, cited here) one should seal the bread in a bag and throw it out in a respectful manner that keeps it technically fit for human consumption. With regard to crumbs, Rabbi Jack Abramowitz of the O-U rules that (for metaphysical reasons) it is preferable to feed them to birds than to just throw them out (presumably, without sealing them). Chayei Adam and Beis Baruch 45:5 (as cited here) permit feeding bread to animals/birds if it will likely never be eaten by humans (regardless of size and actual edibleness). Are these viewpoints all in agreement? If so, is it preferable to throw out bread sealed in a bag or to feed it to birds/animals?