Yes indeed....so true.
I agree. If you want reliable broodies, those that will sit the 3 weeks and even 3 more if the first for some reason fails, and do it again season after season, go to a game or Silkie, and even many bantam Cochins.
My layer types have all been selected for decades to lay well...which means broodiness has been deselected out of them. You can get a commercial layer breed that goes broody, but often they sulk, playing at it, rather than brooding....or brood partially but then poorly mother.
Some of the large fowl heritage breeds have been carefully bred so that some lines are very good at brooding again...my Marans turn out to be that way...they have been overall beautiful and broody birds.
But some have too much commercial blood in them yet, which makes for fickle brooders....and perhaps those are the ones many complain of not having the stamina to brood well.
I've heard Asils are excellent broodies, which amazes me a bit as they are not fluffy like my Silkies or bantam Cochins (who resemble a mop). I know the games are closer to the original jungle fowl, so they have strong brooding (and flying) instincts. I have only had a few game types. I really enjoyed them...lost them as they always managed to get themselves into trouble flying over stuff or getting into stuff.
LofMc