I stole those food coloring and lipstick ideas from somebody on this forum years ago, I have no idea who or I'd give them credit. I can't take credit for those.
If you try it and get results, could you please post photos. It would be interesting to see them. I can only remember one other...
I can't come up with any photos online that look like that either which makes me think it is so common it's not worth mentioning. I would not be concerned about that at all. I'm sure I've seen eggs like that and haven't even noticed it as different.
Breed has nothing to do with those spots...