You can put them in a bator when ever you want. As far as leaving them under the hen, you have to wait and see if she will go broody and then she might not stay broody. For those of us that use bators all the time, a broody is just a bonus. If I have a hen go broody I will usually candle some eggs from my bator and then put the good ones under her to finish hatching. This gives her something to hatch and me more room in the bator. It is a win win situation..
1) I can control what the breeds of the birds are 100%.
2) I can control what day I want them to hatch.
3) I can hatch them any time of the year. No waiting for a broody since most breeds don't set.
4) I don't have to rely on a hormonal bird to reliably sit on eggs and then care for chicks. They do and will get up and stop sometimes.
5) How else could I set 60 eggs all at once? Momma hen would do best with about a dozen or so if she is a large breed.
I like hatching...sometimes its a wait and see if a hen will go Broody for you...I like the idea of hatching chicks when I want or need them...Online here if I see a breed that I am interested in I can ask for eggs and within a weeks time have them in the incubator.....
This time of year you have to wait til the weather co-operates to be able to order chicks from a hatchery, they can die too easy from shipping...
My DD says I have a God complex...i like to control EVERYTHING! DH would probably agree
I agree with what everyone else has to say as far as
1) i can do it when i want to
2) i can control what goes in and comes out
3) i can do it any time of year (and i frequently hatch all year even though i live in MI)
4) i don't have many broody hens
5) i have 'sneakers' who sneak in and leave me extra eggs in the nest where the broody's are, then i have to wait until the feather out to figure out what i have
I have had several times (usually perfect for my dd for fair time) some hen sneak off and i think she's been plucked for good, then 21 days later she trots out a brood of her own. Last year it was 13 babies who DD took to the fair, the year before it was 10...but we never saw them until they finished up the job (hence the CONTROL problems, LOL)