I find the bantams and the silkies are more reliable than most of my larger hens.
One of our year old light sussex started sitting in the nest box = no clucking, but as she was sitting there I assumed she was broody.  I put 8 eggs under her.  She did sit well for 21 days, but not a peep out of her, no clucking, or squawking when I went near.
This morning I saw two little faces peeping out from under her.  Discovered 5 chicks in all.  Three eggs not hatched.  Thought they may be a bit late.  Maybe the hen knows better, as by this afternoon, she had moved to the other side of the pen and left the three eggs.  I have put them under her again, just in case.