What Kind Of Hen Is Best For Incubation/brooding?

The leghorns etc. That are bred for egg production also have the broodiness bred out and the body size for food efficiency.  The big meat birds like black australorps and buff orpingtons lay fewer eggs (over a year) and are more prone to quit laying and "go broody", meaning they hunt anyones'eggs and try to hatch them.  They have the extra body size to weather the 3 weeks of high body temp and little food required for successful hatch.  Many smaller breeds will quit halfway thru.  Both blacks and buffs are excellent moms and good natured.

I would say bantams. That's just from the chickens I have raised. I have has barred rock hatch, but only one out of 30 or so and only once, but she was a great mom.  My bantams hatched multiple times and were amazing moms. I have a buff orpington setting now, so we will see

Silkie are generally regarded as being one of the most (if not thee) most broody chicken.  However they have feathers like hair and are also quite small.  A better breed for hatching is a silkie crossed with a sussex or maran breed. If crossed with a large sussex/maran the hatcher will be able to sit on more eggs than just a silkie.  (Paul)

Basically all of the hens try to sit the nest after they lay an egg, at least for 30 minutes. To say about the kind of the hen for brooding is not possible because it all depends on how you encourage your hen to broody. For complete details about brooding click on the link:
Brooding