Have had a couple of those wee eggs, one I know was from Sophia, she is 2.5 years old. Not sure if she is laying or if it's Blanche back to laying eggs, but there has been a large olive egg in the mix past couple weeks, the old girl Penelope will lay an egg every week or so. But I haven't seen any blue eggs from Buttercup - makes me worried she is laying them somewhere and one day I will find a whole cache of them
When my silkies started laying eggs they were about the same size they are now - they have been laying over a year now. I do think that they a bit smaller once they start laying after they have been broody though.