When to candle incubating eggs?

[Mccluckers]

I have 7 call duck eggs in the incubator (started this morning) and I would like to know when you guys candle your eggs.

Thanks in advance

 

[hayoungyun]

I like to candle at day 1 day 7 day 10 day 14 and day 18.

 

[Mccluckers]

Ok, do you candle at lockdown as well?

Thanks