Thanks for replying. I didn't crack open the larger one - but didn't see any yolk in the smaller one with the soft side. Weirdly, I also found a shell-less egg in their poop tray yesterday. Just one normal-looking egg today but my poor Gingernut looks a bit mucky around her rear end, so now I'm wondering if she's got the problem rather than the Pepperpot. They are still both very lively and look well enough, apart from the mucky bottom.
I'm nervous about looking in the next box every day, wondering what I might find!