My response can only be anecdotal, as I have neither silkies nor any cochin pullets old enough to lay, yet. Most of what I see in the forums is that silkies are brooding fools. Although some folks with silkies have never had one go broody. Cochins are mentioned less often by members, I've noticed, as being broody. Some may be, but I don't see it often in the posts in this forum, anyway.