I shared the info on my housing before but here it is again.
After Thanksgiving and until Spring I house my chickens inside my loft inside garage. First, I only have a few as pets (currently 6). The second and probably very important reason for keeping them there is,,,,,, No need to let them out in the morning, as well as making sure
we are home to lock them up at night. Gets dark early before we get home during winter.
In the garage they have sufficient room in my loft that I made for them and Pigeons. Now since I don't have pigeons currently, I opened up both sections for them to roam. There is light 12 hours on a timer so they don't go nutty.

I also have my water containers kept warm. (electric)
During severe cold, I have a wood stove in garage that I can fire up to take out some of the chill. My cats also sleep in garage at night. All are feral rescue BTW, and fixed,

even though none were really broken.

This year I did not need to use stove very much since it did not get very cold in my area. My goal is not to make it warm in garage, but rather to prevent extreme cold.
Seramas are not very cold hardy breed. Many peeps do keep them in their home. I have no desire to do such, but the Garage heated to minimal during extreme cold worked well. I am still trying to mastermind a heated roost for inside coop. It is during the night that the temps are cold and chickens could use
some added warmth to get thru.
Seramas are feisty enough to be able to get along with LF chickens. They are not aggressive, but do not want to be at bottom of pecking order. What that translated to is,,,,, They can carry their own. My OEGH (2) are the same way.
So here are some solutions for cold weather housing.
@Faraday40 , you can take them into garage along with your roosters, for the cold nights, (separate crate) .
@chickendreams24 you say to DH2B,,,, "Honey, Suzie needs to be in crate in our hallway for this cold night"

. I would avoid keeping in too warm of a spot to not offset chickens accustomed tolerance to cold. During the day seramas join flock on regular basis. There would probably not be that many very cold days where we live. Further north and away from the lake does get slightly chillier.
This was Gorbie inside winter housing. The one that went MIA. Cant seem to locate pix of the other one at this time.
And this is my current flock