Early developing too quickly, plus staggered hatch advice?

[Chocolate_Chick]

So 12 days ago I put 7 eggs in my incubator, only one has developed. Fortunately it's got really good veins and seems pretty strong. It's a serama egg, and it's wobbling at day 12! I've hatched them before and they wobbled at day 15. Yesterday, day 11, I thought I had seen it move but put it down to wishful thinking. Today it definitely is moving. And whats really usual is, in daylight, I can see the embryo moving around - without candling. I can see a dark shape moving on different sides. I didn't know this was possible. The shell quality is good, it is light colored but not as light as some of the others in there. Anyone seen this before? I'm guessing it will hatch early as it is already taking up a good amount of space in the egg.

Now the query, I have 8 more eggs to put in there today, I ordered more I thought I'd need to replace the eggs that weren't developing. All of them have detached air cells, so I plan to prop them up in cut out egg cartons and put them in. Keeping the humidity a little lower to allow the air cells to grow sufficiently. However I will need to hand turn them and turn the auto turner off. So I need to open the incubator 3-5 times a day, while also trying to guess which day the egg that is developing will hatch, as its likely to be early, so I can up the humidity for that day and not shrink wrap it from opening the bator. Anyone done this before and has some advice?

 

[Madi131]

I also have one egg with a detached air sack. Ive kept it in the turner, because it still holds it somewhat upright, it will go on lockdown in 2 days. The egg was from the coop, not shipped so I don't know what happened to the air sack honestly. I've never done a staggered hatch in only one incubator. I have 2 incubators, and I'm about to get a third. Ones for constant incubation with the turner, and the other is for hatching. I put eggs in every 4 days. When they're on lockdown they move into the other. So I really can't give you advice on that..
Now about the development. At day 12 the egg should be nearly full. After day 14 you won't be able to see inside of the egg at all. I'll attach a picture below of one of my Silkie eggs at day 12, 13, and 14. They're also bantams, but no where near as small as seramas. My silkies hatched on days 19-21. I put them on lockdown on day 17 as bantams are known for hatching a day or two earlier than normal sized chickens. I would look up some serama breeders or incubation guides and see if they can help or have any experience with early hatching.