Here at the recue and the rest of the house I do not take a chance. I always slide the screens to the top of the window and open from the top only. This lets the heat out as the heat rises. For our slider I use a piece of thick plastic or thin plywood . Cut 1/2 inch larger that screen. Pre drill holes and screw into the screen frame. Have not had any escapes. Donna Director of The Educated Ferret [Posted in FML 8121]