You will want to rotate your stacked eggs down to the main level on a regular basis. This will help even out the temps for them.It's day 7 for me, so I'll be candling all thirty eggs tonight. For those of you stressed about candling a large number of eggs, I like to keep the eggs in styrofoam egg cartons while they're out of the bator. This will keep them a little warmer, but really, 30 minutes out of the bator isn't a big deal at all. I think cooling is riskier for the embryos before day 7. I do keep the lid on the bator while I candle, so it stays warm.
I know we have lots of folks hatching dark eggs. I think SilkieSensation already pointed this out, but although veins might be hard to see, I usually find that around day 14 I can see some movement. It's sort of like a shifting shadow that you can see near the air cell, or at the bottom of the egg. And you can't always see it. But you will likely see the air cell get bigger, and the dark mass inside the egg get bigger. To be on the safe side, I never throw out very dark eggs unless they smell or leak.
Also, one thing that makes a world difference when your candling...darkness. The darker the room the better, so if you can find a place with zero light, not even the digits on the alarm clock, you'll see more. After you turn off the lights, give your eyes a good 2-3 minutes to adjust before you turn on your candler. It's hard to be patient, but I'm always surprised by how much more I see towards the end of my candling, then at the beginning, when I don't give my eyes time to adjust. While candling I only mark the eggs that are questionable with a pencil. I put an X on eggs that I suspect are clear, and ! on eggs I think may have died, and a ? when I have no idea...but that's just my system.
After candling I always rearrange my eggs. It's definitely a good idea with still air, but even forced air incubators have cool and warm spots. I found a chart that indicates average hatch rates for the various areas in a Brinsea. Plus my eggs are stacked, so I know the top level is warmer. Good luck with all your candling adventures!
I also caved and candled about 1/2 my eggs 2 or 3 seemed clear 2 seem to have blood rings and about 10 had veins I didnt candle the other roughly 10. I only did it real fast because well I couldnt control my urge lol.I see veins!!! I only slipped my hand in and candled a few but they are there!!
I run staggered hatches all the time. Yes, you can set eggs at 1 week intervals or any time really. Here is how I run my staggered hatches when I'm hatching in the same bator that I'm incubating in. Keep humidity as low as possible for as long as possible (30-40% for a still air, 40-50% for a bator with a fan), keep turning any eggs not in lockdown until you see an external pip or hear peeping from an internal pip. Then raise humidity only as far as necessary for hatch (40-60% for still air, 60-70% for fan). I never add water to the wells in the bottom of a styrofoam bator because it's nearly impossible to remove without emptying the bator. I use a bowl with deep enough sides that the chicks can't hop in & put hot water in it. I sit this right on the screen with the eggs as close to the center of the bator as possible. Some people use wet sponges or even maxi pads. If humidity drops below 40% during active hatch I will mist the inside of the lid of the bator once or twice with hot water from a spray bottle. Only 1-2 sprays is usually necessary & humidity instantly rises 10-20%. As soon as hatch completes, remove all babies even if not completely dry (they can finish drying under the heat lamp as long as they are able to stand & have their feet pretty much under them). Remove water source from bator & resume turning eggs not in lockdown. Repeat for the next batch.
I'm still holding out for my day 7, Sat, but waiting is not easy...
