Help candling eggs?

[Velarisduckmom]

My sweet runner, Avocado, has been broody for a week. I was finally able to candle today, but it's my first time and I'm not so sure! Any help reading this would be greatly appreciated.

I made an imgur gallery so they're not all on here! Not the best pictures, sorry in advance!

GALLERY

 

[sarahgray18]

Those all look like they're developing to me!

 

[Nananola]

After candling my duck eggs after 7 days they all show good but only about 1/2 hatch, what might be the problem??