The smaller the coop, the greater the risk of increased moisture. Chicken's loose a lot of moisture through their respiration, and through their poop. All that moisture needs to be vented out. The dripping from your corrugated metal roof is that excess moisture which was condensing on the roof b/c of the temperature change. Then it "rains" back down onto the birds and into the litter. Insulating the coop may have stopped the condensation, but it did not solve the moisture problem. The only way to remove that moisture is by having purposeful ventilation. It's best to take advantage of natural air currents by having a low vent to draw in fresh air, and at least one high vent to exhaust that air which will also pull out some of the moisture and ammonia. Your coop is maxed out in the number of birds that it can hold. The more birds/s.f. the greater the moisture problem. Can you show pics of your coop, inside and out, with a view of each side? (If you want suggestions for increasing ventilation) Your current situation does not have enough ventilation. Louvered vents are great b/c they allow fresh air to enter, while the louvers keep that air from being too "breezy". I do cover my floor level louvered vent by stapling cardboard over it during the "nasty cold" winter months. But, even with that one vent covered, I still have vents at windows, soffits, eaves, and pop door, in addition to the "not so tight fit" at clean out and broody pen doors.