The bees could eventually chew through it first chewing of the gray covering and then working on each of the fiberglass filaments till they work through them all, but it will take them weeks to do this. There is a greater chance of the screening getting torn as it can rip fairly easy. So sorry to hear about the hives, what a bad time to loose them at the beginning of the honey flows. Water the bees need it for cooling. I have dumped cups of it through the screen in the front entrance of the hives.