How long should my silkie be sitting on her eggs?

[CHIC]

My Silkie hen just started laying on a clutch of eggs but she doesn't seem to sit on them very often. How long will it take to hatch? Will she automatically sit on them the right amount of time?

 

[Cuban Longtails]

Unless something goes wrong, it takes 21 days to complete incubation.

 

[Elite Silkies]

A broody Silkie will sit on her eggs faithfully. Only leaving the nest maybe about one hour a day.

 

[CHIC]

Although I thought she wasn't laying on her eggs enough, she has started laying on them ALOT. Thanks for the info