I've chosen the 8x8 walk-in from "Building Chicken Coops for Dummies" and will make some minor changes. I want to build the coop at an easy pace for time and budget reasons.This design is going to take a lot of 2x4's.Obviously untreated is less expensive than treated but I'm wondering how many wet days the untreated framing would be OK if left exposed? The framing is going to buttoned up from the elements of course once the roof and siding is on. Thanks for any input.