First time hatching duck eggs. Worried :(

[MotherDucker3]

I picked up 4 ducks eggs from a local farm on May 22, 2021. By day 7 I realized only one of them was actually fertile and the other 3 were not developing at all.
Now I feel very worried for this one egg I have left. Instead of having 4 chances to hatch ducklings, I only have one... I feel like I'm stressing about this so much, but I really want this egg to hatch. I have been reading and researching a lot on how to improve the chances of a successful hatch. My egg seems to be doing good from what I can tell. I candled today at 12 days and can see some definite movement which is great. Just a few questions:

-I posted a video below from today. Does the air sac look like a normal size for 12 days? I have been trying very hard to keep humidity at 55% since I'm pretty sure this is what its supposed to be. But I find its either too high like 66% or by the time I wake up in the morning its dropped down to 30%. Ive read that too low humidity can cause the duckling to dry out and too high they can drown... Im starting to use a pencil and make a mark on the egg to track the air sac size

-If my baby does fully develop in the egg, what are the chances of a successful hatch? What should I look out for when he/she does pip/start hatching to ensure they don't die from complications?

-Should I mist my egg? I have read mixed reviews on this

-Any other advise welcome!

Thanks for reading<3

 

[cheezenkwackers]

Your air sac doesn’t look bad but I would stop adding any water, momma duck doesn’t. I usually incubate mostly dry 35-40% and my last hatch was 100%. I find too much humidity way worse than not enough because you end up with a baby that is too big to move to zip. As hard as it is, the best thing you can do is leave it be. When you do reach hatch day be aware that ducklings take forever to hatch and again, the best thing you can do is leave it be. I hope it goes well!

 

[MotherDucker3]

Your air sac doesn’t look bad but I would stop adding any water, momma duck doesn’t. I usually incubate mostly dry 35-40% and my last hatch was 100%. I find too much humidity way worse than not enough because you end up with a baby that is too big to move to zip. As hard as it is, the best thing you can do is leave it be. When you do reach hatch day be aware that ducklings take forever to hatch and again, the best thing you can do is leave it be. I hope it goes well!

It's pretty dry where I live, if I were to stop adding water it would drop to probably 20-30% humidity. I'll try and keep it like 40% then you think? And then when the egg goes into lock down I need to increase it right?

 

[cheezenkwackers]

It's pretty dry where I live, if I were to stop adding water it would drop to probably 20-30% humidity. I'll try and keep it like 40% then you think? And then when the egg goes into lock down I need to increase it right?

Yes, you want it high for lockdown. If you have a humidifier you could put it by the incubator, that would increase the humidity in the room and incubator. That way if your like me and can’t keep your hands out you don’t have a drastic change hen you open the incubator.