My best Silkie started being a momma practically the day she hatched. Just kidding, she has been such a great broody. Can't remember a time she wasn't trying to hatch something, anything!
She usually lays for about a week and then wants to hatch eggs. She's five years old now and still tries to get in the nest of other broody girls to hatch. It doesn't take much to make her broody, if I slip an egg or chick under her, she usually will flip the broody switch to on.
That said, she's not typical of my other Silkie chick experience. The other Silkie I had previously must have been born with that switch stuck in the off position because she just would not go broody and she only laid eggs occasionally. She was sadly killed by a hawk while free ranging with the flock.
My second best broody was a Silkie mix (part Silkie, part white leghorn/EE) I called Vanilla Ice. She was a strange little girl but she too could flip on her broody switch with just a hint of fake eggs in the nest. Unfortunately she was murdered by my lab mix puppy when she escaped the safety of the enclosed run and he was loose.