:)

I like din. Thanks, Wendy.

I understand what you mean, 'patter' has too soft a sound for me, like the patter of feet or gentle rain on the roof. How about 'smash' ?
All of these words have a connotation of 'sound'. Perhaps one could add 'din' - There is the din of eggs smashing against the windows. ?

Wendy, maybe: ''Eggs patter against the bus windows'? see: https://www.reverso.net/text-translation#sl=dut&tl=eng&text=Kletteren Kletteren has the connotation of a sound, rather than the act of breaking up.

Mark, I would suggest 'Eggs shatter against the bus windows.' They break against the hards surface of the window. surely.