I have only had one, hit a small white bird on the lower right side of the nose of a Dash-8. Caught sight of it about a half second before impact and felt a thump. Lucky it didn't go thru the prop I guess. On the ground there was no damage, just some feathers and blood. Our company did have a Dash that took a goose on the leading edge of the right wing, going completely through the leading edge and doing serious and extensive damage to the forward spar.
Geese hurt!!