Egg metaphors are weird at the best of times, because they hark back to different times. A bad egg was one that had been fertilised, almost unknown in retail in the west, so I suppose could be said to represent murder and a destroyed life.
So of course a good egg is one that hasn't, apparently at least, been fertilised, so does it represent lost opportunities and vanished hopes? Disappointed ambitions perhaps, or what?
And let's not start on rotten eggs...
But modern egg retail is so sanitised that maybe all the nuances are lost?
But I do like the wasp egg metaphor.