Welcome to BYC! Looking real good! You did a nice job and I'm sure they'll be quite comfy. Just a couple of questions if I may... Have you done anything to add substantial ventilation? It looks like you even closed up the spaces between the rafters... In cold weather, your birds are going to give off a lot of moisture in poop and breathing. That could/will cause some serious frostbite issues as well as air quality issues without a lot of ventilation to let the dry cool air in and the hot moist air out. As long as there are no drafts directly on the birds when they roost, they'll fluff up and be quite comfy down to 20-30 below zero. They are wearing down coats after all. As an aside, the roost will help avoid cold issues as well if it were a bit wider... like that 2x4 turned 4"side up... They'll scootch fwd in the winter so their first toe digit is over the edge then settle down with their keel bone on the roost and their feathers covering their feet/toes. Much more comfy for them in the long run. Probably don't need to say it, but best to get that OSB sealed up post haste!