I read somewhere not long ago that Silkies are really very cold hardy. Here's a link to a different conversation regarding silkies and cold hardiness https://www.backyardchickens.com/t/...-are-more-cold-hardy-than-we-tend-to-think/10
We had several 20 years ago in warmer climate of NM, and am trying again now, but our little roo died last week (on a fairly warm day). We get so cold and windy up here, I tried to really check it out before diving in.
Once feathered they do seem to stay nice and toasty, but it sometimes takes them a bit longer than smooth feathered breeds to grow a full set of feathers. I have mine out in the unheated, uninsulated coop and they seem quite content. They snuggle together at night, but they do that all the time, regardless of weather.
Hens go broody when you don’t want them to… and won’t go broody when you do. 
