That looks sort of in between pimples and sandpaper eggs. It's not that unusual and can be caused by many different things. As long as you are not selling them where they have to look perfect, it doesn't hurt them. Certain hens tend to do that more than others, maybe a flaw in their shell gland. I personally would not try to hatch them in case it is genetic but they are fine to eat.
The egg making process is pretty complicated. To me the surprise is that so many seem to get it all right straight from the start. That may just be a start-up problems or she may continue doing it.
When I have an issue I try to determine if it is an individual chicken or a flock-wide problem. I don't treat the whole flock if it is just one chicken. I don't consider that to be a problem anyway unless it gets way worse. The way you are feeding I don't think you are feeding her excess calcium.
The egg making process is pretty complicated. To me the surprise is that so many seem to get it all right straight from the start. That may just be a start-up problems or she may continue doing it.
When I have an issue I try to determine if it is an individual chicken or a flock-wide problem. I don't treat the whole flock if it is just one chicken. I don't consider that to be a problem anyway unless it gets way worse. The way you are feeding I don't think you are feeding her excess calcium.