Most folks report a broody box or crate can work. I bought a dog crate with intention of trying it on my frequent broody hen, but just have not had the heart to use it. But would if she sits over 3 weeks. There is a danger if they don't come out to eat and drink a couple of times a day. Until you decide to intervene or let nature run it's course you can try to entice her out for nourishment or offer food & water in the nest.
I was quite worried the first time my Big Buff went broody, she really would not leave the nest. And got quite week and clumsy. gave her lettuce, food by hand, and used a dropper for water. Since the first episode she caught on that she had to get out some comes down 2x day to eat and drink.
I do know that the longer they sit, the longer it takes for them to restart laying and each time they become broody, they have to re-establish their place in the pecking order. And find it quite irritating to all.
If you are interested in the broody breaker boxes/crates, do a search in the forums, there's lots of specific info on how others do this.
