PLEASE HELP!!! Aircell problems???

[Tofu the chicken]

So this is my first time hatching eggs, I had gotten some Muscovy eggs shipped to me, sadly usps is having problems nationwide and it took 6 days in 80 degree heat for them to get here, (luckily got refunded), most eggs were dead on arrival, some started development but only one got past being just blood vessels, I have been using broody silkies to hatch the eggs the last Muscovy egg is currently on day 18/35, last night I saw it moving in the egg for the first time, but it has occured to me that the air cell is way too big, I had been spraying in and around the nest and soaking moss to put close to the eggs but not enough to soak the eggs (I also put pekin eggs under my hens, I have multiple broody so I'm not worried about delayed hatch and they will only hatch 3 days apart they are on day 8/28) anyways I did that a few days ago but stopped cause I looked up my local humidity levels and it's in the 70s-80s for the next week at least but the air cell still grew a bit from yesterday, I'm open to any suggestions thank you, I really want to save this last egg

 

[WVduckchick]

Day 18 should show more development than that, and half the egg should not be air like that. Are you sure you saw independent movement, and not just movement caused by handling the egg? Are you positive on the day count? If so, i expect it will either quit, or it hasn’t been covered enough to develop properly.
Also, being all on one side of the egg, indicates that it wasn’t being turned properly.

I would not spray any more water or try make the nest more moist. It could promote bacteria growth, and is not going to help the egg.
Folks who hatch emu eggs sometime slow down moisture loss by adding strips of tape to the egg. You may want to look into that option. I’ve never done it, so can’t say for sure the best methods or what kind of tape, etc.

Good luck!