Are egg colors/speckles supposed to vary?

[Jen-the-Hen]

These are the eggs I've gotten for the past week or few days.
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I have two started pullets of unknown breeds (one might be a mix with sapphire gem,) and several pullets that should start laying in just a few days. I wouldn't put it past them to start a little early- and that darkest, speckled one is a bit on the small side. But I digress.

I thought that one hen layed a tan egg and the other layed a darker brown, speckled egg. This is evidently not a solid fact! Sometimes they're speckled, sometimes not.
Is this normal for a hen's egg colors or speckling to vary? Or do I have some sneaky early pullets? Is it parasites/some exotic disease?

Yes totally normal and natural. Unfortunately we've been so conditioned to uniform veges and eggs in mass production these days, that anything else gets rejected. Your girls' eggs look lovely.