Let me start by saying that it likely doesn't get as cold here as it does there. However, we have had a freaky winter this year with temps down to 2 deg and consistent night temps in the low 20s.
Silkie #1 hatched out three standards and a banty chick back in December. She was in a plastic dog crate nestled down in the shavings in an uninsulated coop. I was worried about the babies as well, but all four are thriving! On the coldest of days mama brings them back into the coop to scratch around out of the wind. When somebody got cold they would run up under her and she would hunker down and warm them up. Then off they'd zip again. All four have completely feathered out and are mostly out in the run doing chickeny things these days.
Silkie #2 went broody a week and a half ago. She won and is now sitting on 7 eggs. So far all is well. The funny thing is that the babies from Silkie #1 have figured out that silkie#2 is a willing stationary furnace and now snuggle up in the nestbox with her when they get chilled.
If they have an insulated protected area you might give mama hen a chance. Just keep an eye on them. It's always possible to move them all inside on the coldest of nights if need be.
Good luck!
Silkie #1 hatched out three standards and a banty chick back in December. She was in a plastic dog crate nestled down in the shavings in an uninsulated coop. I was worried about the babies as well, but all four are thriving! On the coldest of days mama brings them back into the coop to scratch around out of the wind. When somebody got cold they would run up under her and she would hunker down and warm them up. Then off they'd zip again. All four have completely feathered out and are mostly out in the run doing chickeny things these days.
Silkie #2 went broody a week and a half ago. She won and is now sitting on 7 eggs. So far all is well. The funny thing is that the babies from Silkie #1 have figured out that silkie#2 is a willing stationary furnace and now snuggle up in the nestbox with her when they get chilled.

If they have an insulated protected area you might give mama hen a chance. Just keep an eye on them. It's always possible to move them all inside on the coldest of nights if need be.
Good luck!