I know this is an older thread but nevertheless it is still very relevant. So I will share my experience with broody hens.
I have kept chickens in my yard for at least 8 years before I moved to the city so that I can support my family with some extra money. My parents, my younger sibling and my grandmother is still maintaining a flock of 300+ chickens back in my home. I have seen hundreds of hens of different breeds and cross breeds going broody, from silkies to Leghorns to Cornish X.
What I have experienced is that while silkies are very broody and are sweet they are just not fit for the job. They are not competitive foragers, they tend to remain on the bottom of the pecking order, they can't defend themselves and chicks from bullies. That being said they are full of love and passion for the chicks and love being mothers. But you have to separate them from the flock, you have to make a different arrangement, you cannot free range them, you cannot leave them with the rest of the flock, in a way they kind of sabotage the whole idea of having a dependable broody hen under which you can throw a dozen or 15 eggs and then leave everything upon her.
If you are looking for the best dependable broody hen on which you can trust in my experience you will not find a better mother than an Aseel hen. Because...
1) they are very broody, they will go broody atleast 3 times a year. Most of mine go broody 4 times a year and trying to break a broody Aseel is like trying to break steel with bare hands. It's next to impossible.
2)You don't need to separate them from the flock, trust me no one will mess with a broody Aseel.
3) They are always on the top of the pecking order, this means their chicks are well fed.
4) They are excellent foragers.
5) They are most intelligent of all chickens.
6) They are very protective mothers, they will not tolerate a mean rooster, I have seen them attacking snakes, dogs, foxes, cats and crows in order to protect their chicks. But they will only attack when their chicks are too small to run fast, they just cannot abandon them for sake of her life.
7) They are very good teachers, I have seen them whacking a slow learner.
So in my opinion, based on my personal experience Aseels are the best mothers you will ever find in the chicken world.