So I put 18 SLW eggs in the bator and candled at day 7. 4 were difficult to tell, the others were fine. Today is day 12, candled again and 2 out of those 4 were fine too. Now, the quandry: In the last 2 eggs the air sacks have developped just like the others (I used a pencil to trace the outline), but they're difficult to "read" (I don't have professional devices for candling, I use a 25W light bulb in a dark box with a hole in it ) In one egg the shell looks like it has lots of spots where the light shines through, it kinda looks like a shade in there but not as distinct as the others. In the other it looks like there's a line around the bottom part of the shade - I immediately thought blood ring, but I've seen blood rings before and it doesn't exactly look like one. Could it be just a blood vessel that runs along the edge? Now, as the air sacks are developping just like the others I'm not too keen on throwing them out in case there's nothing wrong really - can I leave them in as long as they're not seeping anything? Do I need to candle them again? I'm not planning on candling again until day 18...? I've never had any trouble when candling before, the eggs have either developped fine, been infertile or had blood rings (a couple).