Candling Muscovy Eggs

[Gobbles3]

Hi all, usually I just leave my Muscovys to do the hatching themselves but they went a bit overboard with eggs so I put some in my incubator. At what stage should I expect to see some development? They've been in for a week and they don't seem to have started developing.
Also if anyone has some helpful hints or an incubation guide I'd love to hear them because I hatch mostly chickens and guinea fowl and have never had a lot of success with duck eggs.
Thanks in advance.

 

[oldhenlikesdogs]

Here's an article that may be helpful,

https://www.backyardchickens.com/articles/incubating-and-hatching-muscovy-eggs.63532/