Yes, cows can drop zod rune, or at least I think so, but anyways I've never really found any good rune in The Moo Moo Farm besides from the stashes that are around. The stashes drop good stuff and no one seems to open them. Yes, I used to do Bloody Foothills runs and that place drops good runes, I found jah, cham, ist, etc. there many times.