Sorry.. but lack of ability to see only goes so far. I started with two silkie chicks in my flock, Raven and the then Smokey. Neither had a crest developed enough to hinder eye sight.. but one night when it rained hard, instead of following the other 8 chicks into the coop, they moved to the lowest point in the run and, as far as we could tell, drowned. Had they moved a foot to the right, they would have been soaked, but fine. Had they moved with their flockmates into the coop, they would have been damp and fine. We lost Raven, but Smokey managed to pull through and was renamed Stormy.
Out of the lot, 2 were completely dry (the largest slw and columbian wyandotte), 6 were wet (everyone else except the silkies), Raven was dead and Smokey soaked and badly chilled, an inch from death (my parents said it took 2 hours before she could even stand again).
The little survivor:
As you can see.. you can still see her eyes clearly and Raven was the same way. So the "crest blocking vision" does not explain what happened here. Stupidity does. Not that I don't love Stormy anyway.. she does look adorable when she runs with those cute little fuzzy legs!
edit: misspellings.. rofl..