I use plexiglas panels in the windows of two coops, only during the winter and rainy seasons. In the A-Frame, with the slanted walls, the two windows have hardware cloth coverings on the OUTSIDE, larger than the windows, with the staples not covering one end, so I can slip the plexiglas under the hardware wire. The plexiglas is also larger than the window opening; the hardware wire holds it tightly to the coop sides, so there is very little seepage or leaking.
In the traditional coop, I just cut the plexigals panels to fit inside the window openings. The windows are under roof overhangs, so there's also very little leakage from rain.
In the traditional coop, I just cut the plexigals panels to fit inside the window openings. The windows are under roof overhangs, so there's also very little leakage from rain.