Despite not being super common or prone to happen.. it's happened way more often than I would have expected and I do see stories on here all the time with successful sex link and even leghorn broody's. So the likelihood is low, but very possible.
Broodyness is a natural (hormonal) behavior and beyond genetics is best encouraged by good shelter, good nutrition, good internal/external parasite control, and plenty of space. Leaving eggs in the nest or collecting EVERY day makes NO difference
for chickens.. a broody chicken hen will brood air if she has to (she will sit on the egg she lays that day). A completely empty nest may be thought of as raided (by the smarter hens, seriously) and so I do suggest leaving at least one fake egg per nest.
Commercial Silkies tend to be less broody than breeder ones, for the reasons mentioned by jacinlarkwell.. broody hens are often out of lay for 9+ weeks at a time. Some of my Silkies went broody by their third week of laying and just about every other egg thereafter. Excessive broodiness is a nightmare. Many go broody once or twice per year, and those are a nice balance. A hen that goes broody once will likely do it again. Some hens may not go broody until their second year.
In all honesty.. incubators are awesome and broody's are not set em and forget em or convenient at all. They often require assistance including, nest hopping, homicidal hens, hawk losses, and so on. Broody families ARE amazing though and it's a cool adventure (definitely with some conveniences) if you're prepared to deal with the extra cockerels, have the right set up, and such. I have adopted sexed feed store chicks to broody hens also. Do you have a rooster already, or getting fertile eggs elsewhere?
I thought I might never get a broody hen.. then I had a glut of them (Marans, Silkie, Wyandotte) with the best being a mature hatchery barred rock. The possibilities are endless, hope you have many wonderful adventures!
