Depends on the type, doesn't it?
I know Lear inner passenger windows (they're two of them; an inner and an outer) are actually a little pliable (not too much force). The outters are not moveable.
Cockpit windows (Lear) are actually 2 layers of acrylic plastic about 3/4" thick.
Not frozen, a frozen chicken has the density of a bowling ball. They were dead, previously frozen, dethawed birds. Old wives tale that the Brits heard about our windshild testing and kept shooting out the windows of their planes until we told them that we defrosted the birds first.