Windows are fixed, here is link to Amazon: https://www.amazon.com/gp/product/B005HPGT30/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1

Few lessons learned: 1-Frame to standard 4' wide siding 2-Original design was too tall, cost two extra 4x4 posts 3-Over hang the nesting box lid to account for trim

The thing is way over built, but should last a long time.