Is the run above that roofed? That would go a long way in helping to protect any vents.This is what they advertise:
this item has ventilation slits on the front and both sides of the unit.
Suggestions on venting? Cut rectangle windows on 2 sides? Will it be too cold if put mesh door back on?
Also keep in account wind direction. I think the triangles on the side would be the best place to think about opening up, but only if your predominant winds don't blow that way. Not sure how hard this material is to cut (some sort of plastic it looks like) but if possible you'd want to save the cut outs so you can hinge them over the opening to help further blunt winds and precipitation, like so:
https://www.backyardchickens.com/threads/the-coop-is-done-now-for-the-run.1381538/ and https://www.backyardchickens.com/th...do-members-think.1498249/page-2#post-25025344