I have never seen the beat of Silkies for going broody. I have had some that, if they saw 3 eggs in one nest, would settle down and fight you for them, every single day for months! One time, the top hen in the pen went broody, and the others kept sneaking in and laying eggs in her nest while she was out feeding. She'd come back, kick them out, and go back to setting. When the first eggs began to hatch, I removed the chicks, and she went right on brooding the rest of the eggs. Every few days, a couple more chicks would hatch, I'd remove them, and on she went! This went on for something like three months before I finally took pity on the poor bird, and removed all of the eggs, candled them, and put back the ones that were furthest along (the remainder went into the incubator). They hatched a few days later, and still she sat; I began to fear that the chicks would starve! Eventually she did get up, but I still had to watch her, she was one of the most egg-obsessed hens I have ever had.
Around here, Bantam Cochins run a close second for broodiness, which I am beginning to think is contagious. Last week, one free-ranging hen decided to set in the back of one of the horse stalls. Two days later, she had competition, which they eventually got sorted out with hen #1 moving to another corner (where three other hens had very graciously deposited their daily contributions). A couple of days after that, nest #1 attracted a third hen, and the two girls divided the eggs between them, setting up nestkeeping within a couple of feet of each other. Yesterday, I moved all three of them (and their eggs) to individual cages, but not before hen #4 got into the act. It was beginning to get so crowded in there, the horse (a mini) had nowhere to stand!