I decided to add some other stuff.
I have Red Star Sex Links to lay eggs for selling. They are great layers. This breed is not known as a great setter, but I always have a few who didn't read that about the breed. Mine were hatched March 12, 2007. I now have 2 that have gone broody. I have let this breed set before & they made good mothers. Since I want eggs, I don't often let them hatch.
My advice to you would be to throw out the eggs that are in the nests. All of them!! Collect all the eggs every day and eat them.
When one of your hens decides to go broody, you will know it. She will not get off the nest. She will be fluffed up and if you take her out of the nest and put her on the floor of the coop, she will just sit there and fuss loudly at you. If she has not gone broody, when you take her out of the nest, she will leave.
There is no need to waste good eggs for no reason. They will go broody without anything to set on, and they will be laying regular anyway, so you will have eggs to put under her when its time.
To my knowledge, there is nothing you can do to make a hen go broody, they will when they are ready.
Some breeds are naturally more broody than others, like the ones mentioned in earlier posts.
Make sure you have a place set up for your hen to raise chicks in when one decides to go broody. Move her into a nest in the area you have set up for her. You need to watch her, she will need to be setting in the new nest for at least a couple of days to make sure she doesn't break up "stop wanting to set". Then you can give her eggs to set. Usually you can just lay an egg in front of her & she will scoot it under her. Otherwise, you can put the eggs under her, but watch out, she will peck & fuss at you. You can do it after dark & it will be easier for you.
Hope this helps you
Jean