Q. My Jewish neighbour’s rabbit died during pesach. After pesach, she gave me the leftover chotzdig rabbit food which I know she didn’t sell. Can I still use it? If not, it seems like bal tashlis to throw it out as it was a freshly opened bag.

A. If a Jew transgresses the Biblical prohibitions of “baal yeroeh or baal yimotze” (not to see – not to find), and keeps chometz in Pesach, it becomes forbidden forever by a rabbinical prohibition, as Chometz Sheovar Olov Hapesach. This penalty applies whether the infringement was violated deliberately or unintentionally, and even if one was completely ignorant of the prohibitions of chometz. (O.C. 437).

However, Horav Shlomo Miller Shlit”a, after inquiring about the composition of the pet food, advised that it is permitted, due to of a number of reasons. Even if the main ingredient is wheat middlings, it may not be chometz at all, since it may not have come in contact with water. It may also be considered a mixture of chometz (taaruvas chometz) as more than twenty other ingredients were listed. Most likely it is only chometz nukshe, either because it did not become completely fermented, or it is not a preferred human aliment (hard pellets). In all this cases, the penalty of Chometz Sheovar Olov Hapesach does not apply.

Horav Miller, rejected as an additional Heter, the opinion (Sheilas Dovid) that chometz of a mummer is like that of a gentile, and therefore permitted.

Rabbi A. Bartfeld, as advised by Horav Shlomo Miller Shlit”a