Right now, I have a broody OEGB that sat on two eggs and hatched them out the day after St. Patty's day.  On St. Patty's day I picked up my chick order from Farm and Fleet, 2 ducklings (of which I have no ducks to hatch out), 5 Polish and 5 (plus a bonus 1) Jersey giants.  So, of all of the chicks, without an incubator I would have two.  I love watching momma and Boo and Kai in their run.  I worry about them constantly because the weather has just been your typical moody Chicago spring, and they are growing big and strong and healthy.  So are the ones from Farm and Fleet.
NOW, I have 18 eggs in the brooder with another 12 chicken and 4 goose going in tonight.  I don't have any geese so there is no way I could have watched natures miracle, but now I can give nature a hand and watch it from the comfort of my library!
I love my broody hens, but of my 35 chickens, I only have 2 broodies.  They could never hatch out all the different eggs I want to have hatch.  I will let my broodies hatch eggs maybe once a year, but I don't want them to stress themselves either.  I love them too much.