Definitely COCHINS or SILKIES. Mine set much of the time. MUGGSY, a Sizzle, a Silkie/Cochin is broody atleast five times a year. My Frizzle Cochin, Slinky has been broody since June 9.
I don't consider myself to be an expert, and I know the reputation that Silkies and Cochins have, but out of all the breeds I have or have had, the only one that has gone broody is my Cuckoo Marans. A friend of mine has just a couple breeds, and it is the CM that has gone broody, also. I' m not sure that is typical, but there it is.
There are a lot of breeds that tend to go broody. I have broody EE's and Australorps at present, and my best broody and mama was a Kraienkoppe (Ideal carries them.)
Here is info on the various breeds, including broodiness and whether they make good mamas:
All my cochins big or small, silkies,frizzles and buffs O here.
Then we get a few EE ,WR ,PR ,BA, SLWD and RIR's.
I don't like dealing with broodies, most of mine will not leave the nest even after the chicks have hatched,they will sit on the chicks till they die if i do not keep a watch for them as they hatch.