The sheathing is next. To cut out the front openings for the nest boxes and door, tack the front sheathing in place. Use small galvanized naile and put one in each corner of the sheet, leave 1/4 in of the nail esposed. Get it all in place with proper overlaps and placing.
Mark around the openings from the inside, remove the sheathing, then cut out the openings. Replace the sheathing and nail on all studs, cross pieces, and rafters using a 6 in. nail schedule.
If you have a router or a Roto-Zip tool, there is an easier way to cut out hte openings. Completly nail the front sheathing in place. Srill a small hole in one corner of each opening. Choose a hole size that allows clearence for the router or roto zip bit. From the outside cut the openings using the studs and cross pieces as the trim guide.

This is the coop with the front paneled and openings cut out.

Do the same for the ends. The only openings are the entrance doors. Assemble the roof panels using galvanized nails with a 4 in. nailing schedule.