Oh no silkies are not good in the winter and neither are frizzles. I lost 2 silkies and 3 frizzles last winter.
Chantelcers, Wyandottes, Delawares, Dominique, Jersey Giant, Javas, hamburgs, cornish, cochins, buckeyes, brahmas, australorps, Ameracaunas, langshan, modern game, turkens, old english game, orpingtons, Plymouth rocks, rosecombs, sumatras, sussex, and welsummers are very cold hardy. There was more on the list but I did not put all of them. Here is a link to the Breed chart. It has lots of interesting info on it.
http://www.ithaca.edu/staff/jhenderson/chooks/chooks.html
I had great results with RIR, EE/Ameracauns, and brahmas last winter, they laid all through the winter! I did not have an issue with frost bite on the hens, I did have a few of my roosters get nipped. This year I will use vaseline to keep them form getting bit. Good luck to you.
I have mixed breed eggs available right now for cheap
$10 a dozen that's shipped. I have all kinds of different breeds, you can read what all I have in my signature! Let me know if you want some.