Dear Rav Kornfeld,

I review a daily daf summary by email. Would you please tell me how to look at a situation which is a combination of daf 78 (courtyards separated by a ditch) and daf 79 (courtyards separated by a haystack)?

On daf 78 we have a ditch which is too deep for people to cross. If one filled in the ditch with hay, the courtyards are still considered separate because stubble and the like are only temporary.

On daf 79 we have a haystack which starts out tall and large enough to be like a wall, and the courtyards are separate. If animals eat from the hay and it becomes less than the minimal size of an insurmountable wall, the courtyards could be joined.

I would like to consider an obvious combination of these two scenarios and ask which daf's reasoning would be dominant.

Suppose I have a haystack over a ditch?

In short, if animals, on Shabbos, ate the haystack down to less than the minimum size for a wall would we use the reasoning on daf 79 to permit joining the courtyards? Or would we use the reasoning on daf 78 to say that hay cannot be used to fill in a ditch, and they remain separated?

I think the analysis might also need to take into account that the haystack lasts multiple days.

Also, as a side note, if it were 2 days of Yom Tov adjoining the Shabbos, to the degree that eruv is applicable for Yom Tov, does it factor in to the analysis that something newly created (revealed) on Yom Tov is more stringently prohibited as mukzeh, than if it came into existence on Shabbos and could not have already been prohibited?

Each strand of hay already existed, but the wall, or non-wall, or bridge, that the hay forms, or is re-formed into, might not be seen as already existing by this rule of Yom Tov.

--Chaim Chesler, USA