We have a Partridge Cochin, Little Miss Muffet, and she is extremely good a t brooding ( this being her first time), she has been sitting on eggs since feb 11 and she will only leave the nest once a day to stretch her legs, for 20 or so minutes. She however has not been a great mother, yesterday she squished one of her newly hatched babies to death, at least that is what we think happened, the baby was flat when we found it under her.
I also heard that Silkies are really good brooders.
my buff orp. is the best setter and mother ever. She hatched out her baby (i only let her have one) on Christmas, and is still sleeping with him under her wing. She protects him, and managed to keep him warm (as an egg from november-december) as a chick throughout January and February in super sub-zero vermont... we had days that were way, way below zero... She's my hero!
My understanding is that Welsummers are not overly good mothers. We had a roo turn up in our Welsummer chicks last year and easily found a home for him because apparently the males actually tend to be the better mothers.