https://www.bbc.co.uk/news/av/uk-eng...gh-speed-train

I was actually working near Swindon when they were testing these in the early 1970s.
They didn't have that sloping driver's window in the first tests.

But they considered the possibility of collision with birds.

In the first tests, they got some chickens from a local butcher,
and fired them in a wind tunnel at the train front, with a crash-test-dummy where the driver would be.

The chickens smashed through the window took the head of the dummy and dented the rear of the cabin.

So for the next tests, they used the sloping window design.
They also defrosted the chickens.