Has anyone ever had luck starting eggs in an incubator and then moving them under a broody hen?
 
Back story (its a little long, bear with me!):
 
Being relatively new to the chicken world, I was VERY excited to have my first broody hen.  I moved her to a nice separate area, started collecting her eggs and giving her fakes, and even ordered 1/2 dozen fertilized eggs to supplement, thinking she wouldn't lay many more before sitting full time.  The trouble is, she couldn't decide whether or not to sit!!  For nearly a week she would sit on and off throughout the day, and was still laying.  She was taking her time and making me worry like crazy! 
 
So I decided to let nature take its course -- I stopped collecting and hardly checked on her for 2 days, and it seems like that's what she needed to settle in.  She's now sitting since yesterday afternoon and has 1 or 2 of her own eggs under her as well as some fakes.  
 
I'm thinking about starting the rest of the fertile eggs (10 total) in an incubator before sneaking them under her in 3 or 4 more days.  I definitely don't want to disturb her right now given how choosy she has been, but I also want to make sure the eggs all hatch at the same time, and I'm worried about the age of my fertile eggs, which are between 4 - 7 days old. 
 
Has anyone had luck with this?  Alternatively I could do the incubator full course and then get them under her after they hatch, or I could wait a few days, scrap the ones currently under her and place the 10. 
 
Any advice?