In which it is found Quail eggs are incredibly difficult to candle...

One of my favourite activities is sitting in a dark room, clutching my 'egg torch' and checking for signs of life inside those little shells.  Tonight I've discovered two of my Quail eggs are probably clears (that is, they are infertile) and ten of them might not be. Thats as good as it gets. They are fiddly little buggers to handle, and because of their dark mottled pattern and fairly thick shell almost impossible to see through.  So now all I can do is wait. I'm not going to handle them any more as I don't think it does them any favours, and to be honest I don't think it will tell me much more.  I'm slightly concerned about one which looked vaguely like it had a blood ring, I really don't want any bad eggs going explosive on me (or on them more like!).  I might have to re-check that one in a couple of days and if in doubt, chuck it out - better to lose one possible viable chick than all twelve.