Silkies are some of the best broody chickens out there, if not the best. you might also try cochins, I personally dont own any cochins but, I have silkies, and when I got it this yeah back in march, it took her less than a month for her to go broody, she hatched 9 out of 9 eggs she had under her.
good news on the cochins! my first one was broody in january before she was even a year old and did great even with the cold Colorado winter we have here. I like her so much I got a blue banty cochin this year