Leghorns are supposed to carry a gene that represses brown pigment on the shell. The fact that yours doesn't means that she's probably a bit poorly bred.
The rough egg can be a sign of something wrong in the egg factory. It can be a sign of not having enough calcium, phosphorus, or vitamin D (all essential to nice egg-shells) or maybe she's just not finishing them because of something wrong in the mechanics. If it's the latter, it might sort itself out, and it might not.
I do get rough eggs from my flock, but they're from the six-year-old, who occasionally also lays soft-shell eggs. Because she's not completing the egg-shell, she may have time to make and lay more than one egg. Usually, it takes 24-26 hours to complete the entire egg, including shell.