Short answer: For chicken coop windows, 1/8 in. clear acrylic works for openings up to about 18 × 18 in., and 3/16 in. or 1/4 in. for larger ones. Acrylic handles sun and cold well outdoors, weighs half as much as glass, and won't shatter into shards. Mount it with oversized screw holes so it can expand in summer, and keep hardware cloth behind any window that opens.

Why acrylic beats glass in a coop

Chickens startle, flap, and occasionally fly straight into a window. Glass can break into sharp pieces in the bedding; acrylic has anywhere from 2 to 20 times the impact strength of ordinary glass of the same thickness (the figure depends on maker and test) and doesn't shatter into shards. It's half the weight, so it won't strain a light coop frame or a pop-out wall. And it's easy to cut to whatever odd opening your coop builder left you.

Daylight matters to laying hens. More natural light in the coop helps keep them active, and a window near the roost lets you see in without opening the door.

What size and thickness to choose

Measure the rough opening in the framing. If the window will sit in a rabbet or behind trim, add the overlap you need on each side (usually 1/2 to 1 in.).

  • 1/8 in. for windows up to about 18 × 18 in. Light and inexpensive.
  • 3/16 in. for windows up to about 24 × 24 in., or anywhere wind loads are higher.
  • 1/4 in. for large windows, doors with windows, and walk-in coops where people brush past.

Clear, frosted, or tinted?

Clear lets in the most light, about 92% of it. Frosted (1/8 to 3/8 in.) diffuses sunlight so you don't get a hot bright spot on the floor, and it gives a bit of privacy if the coop faces a neighbor. Gray or bronze tint cuts glare and heat on south- and west-facing walls in hot climates. A coop in full summer sun can overheat, so don't add big windows on the sunny side without a way to vent or shade them.

Outdoors: sun, cold, and expansion

Acrylic is one of the best plastics for outdoor use. It doesn't yellow noticeably over many years of sun, and it stays usable well below freezing, though it gets more brittle when cold, so don't drill or hammer near it in winter. Read more in can acrylic be used outdoors and acrylic in cold weather.

The thing that catches people out is expansion. Acrylic grows and shrinks with temperature about eight times as much as glass. An 18 in. window moves almost 0.08 in. across a 100 °F swing from winter night to summer afternoon. If it's screwed down tight, it will bow or crack at the holes.

  • Drill screw holes about 1/16 in. larger than the screw, and use washers or pan-head screws. Don't overtighten.
  • Leave about 1/16 in. of clearance on each side when the window sits in a frame or rabbet.
  • Keep screws at least 1/2 in. from the edge.

The thermal expansion calculator works out the clearance for your exact size and climate.

Predators and ventilation

Acrylic isn't a predator barrier on its own. A raccoon can't break a well-mounted panel, but it can work at the edges of a loose one. For any window that opens, mount 1/2 in. hardware cloth behind it on the inside so the coop stays secure with the window open. Coops need ventilation year-round, so think of acrylic windows as light and weather protection, and keep separate high vents open.

Tip: hinge a window at the top so it can prop open as an awning in summer. Rain runs off, air comes in, and the hardware cloth behind it does the security work.

Enter your window sizes in the instant quote. We can drill the mounting holes so they're ready to screw on.

Questions

How do I clean dusty coop windows?

Coop dust is gritty, so rinse it off with a hose first, then wipe with soapy water and a soft cloth. Wiping dry dust across the panel causes scratches.

Should I use polycarbonate instead?

Polycarbonate is tougher and worth it if the window is low where kids, dogs, or hail will hit it. For most coop windows, acrylic is clearer, stiffer, and holds up to sun better.