A lot longer than I expected. I would say maybe 80-90 hours total, but I didn't even start it until after we bought the chickens. Bad idea! The basic frame, not including the nesting box, took about a day. The nesting box was probably the toughest part with all those angle cuts. The plywood siding has decorative grooves in it, and it was also a pain to get those grooves to match up to create a continuous pattern. I am working on some blueprints for you all, and that should cut the build time in half.