Why can't your Silkies puff up their feathers to store heat? Are they damaged, or are you referring to the shredded feather type?
I've raised and have been breeding Silkies off and on (mostly on) for around 8 years (most of my chicken keeping career, if my mind isn't failing me, that started about 10 years ago). I honestly don't see what all the fuss is about regarding them being fragile. Mine go out in the rain, wind, sleet, snow and ice. They step in puddles, they scratch in the mud, its been so cold out that they've had little ice cycles in their crests from bobbing them in the waterer while getting a drink. Their coop isn't insulated, but it is draft free. I stuff a little extra bedding in there before winter when I do my clean out, thats it. They have all of their toes and they never get sick. I've raised them in two states (VA and TN). My experience is they're hardy little birds, and they tolerate and lay well in the cold (which is what I'd expect from a breed that supposedly originated in the Himalayas). They do seem to suffer a bit in our hot, humid summers here in TN, but a frozen can of corn or watermelon and plenty of cool water and shade sets them to rights. I mean, aren't most of the coats we wear stuffed with down? Which is sort of the "under coat" for a chicken, and very similar to the barbless feathers of the Silkie?
Just my experience. Maybe particular breeders lines are just more robust than others? I don't know, but mine don't get any special treatment. If they want to go outside in the weather, the door is open for them. And mine seem to enjoy scratching around in the snow, they're normally the only breed out and about in it. My Olive Eggers, Easter Eggers and Marans go all "flamingo" standing on one leg looking miserable.