I have six sash windows and one crank window in my chicken coop. We have the usual predators (raccoons, coyotes, foxes) but the worst ones are the fisher cats. All the windows have 'house screens" in them and I know these screens would not stop a determined predator. My problem is I need access to the sash windows to open and close them for proper ventilation and at the same time I want to keep the house screens in the sash windows to keep out yellow jackets and other inset pests. I can't cover the windows inside with hardware cloth since I would not have access to the sash windows to open and close and at the same time I would prefer not to put hardware cloth on the outside of the windows due to aesthetics. I was thinking of finding a firm (not rolled) type of metal fence material with appropriate size openings that I could cut to size, hinge on the top, hinge up when I needed to open or close the sashes, and secure when closed at the bottom. Does anyone have a suggestion for the type of material with the following characteristics: not rolled, firm enough to open up and down when hinged at the top, suitable size openings, tough enough to stop a predator, able to cut to size?