I have to agree with dlhunicorn about thier care. Right now they are on medicated chick starter, because I KNOW they have never had it. I have tried to keep thier "snacks" to a minimum but how can one resist? They love tomatoes, and veggies.They also get DE in thier feed, and have been dusted for lice/mites. I have not seen any on them, just wanted to be sure. Thier legs may be a bit more sensitive to the cold because of thier condition. They have all put on weight since they have come here...and thier eyes are bright, and they are alert.
I do not normally have silkies or banty chickens, so I am not sure of the hardiness in the snow. I would have to suggest they just be watched closely with the cold weather.