Some hens are going to be crazy broodies, and others won't. It all depends on the hen and the breed. BUT there are a few ways to encourage sitting on eggs. One way is to put fake eggs in the nesting box. If you wait for a while, a broody might notice the eggs and her maternal instincts could kick in. Also, be sure to keep the nesting boxes free of mites and lice and other critters, in addition keeping it clear of chicken poop, cause even hens don't like grossness.
Keep in mind that even if a hen goes broody, that doesn't necessarily mean that she will be a good mother. For some hens the broodiness is just hormonal and they are following instincts, but others are a natural.