Yep, warm moist air from the chickens is condensing at the thermal gradient - the metal roof partitioning inside from outside. It **should** bead up then run down the inside of the roof. till it hits something. Do the ridges of the roof run parallel to the rafters, or perpendicular??? (or asked another way, is the roof attached to purlins which are secured to the top of the rafters?) Basically, I'm trying to ask what the water is hitting that causes it to drip.
and do you have a scrap piece of tyvek/house wrap handy??