The north wasn't a place for mages with naturally thin frames and hairless bodies - except for the long beards many had as they got older.
When the mages from Nickron arrived in Chemois and realized they were stuck for the winter, they had a stray knight retrieve the former maids and servants so that they wouldn't have to figure out how to keep such a large place warm. After all, their magic stores had already been depleted after having such a difficult time cleansing the place of the black poison.
Other than the temperature issue, the mages had a comfortable time staying indoors and benefitting from a place void of a leader so they felt they were free to browse the personal library of the former duke and use the nicer rooms as they pleased.