Good news, its built right. Suspect your drips are coming where the water running down the metal roofing panels hits the purlins - the thin boards perpendicular to your rafters. Apart from housewrap, I've no good recommends for breathable materials that won't let water droplets pass when they...
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...