Seriously, building a glass strong enough to withstand bird strikes is not a n issue and hasn't been.
The issue is that the glass has to be weak enough to allow the pilot to break through when he's ejecting. So strong enough for a bird at 800 mph, but weak enough for a human ejecting at maybe 10 mph.
That shouldn't be an issue. The canopy is jettisoned before the seat is ejected. The ejection seat doesn't need to break through the canopy.