Chickens don't use each other's body heat in the winter and don't need to huddle for warmth, that's a myth. The whole point of their nice insulating feathers is to not lose heat to the environment. So there's no heat escaping the chicken through the feathers, or else the chicken would freeze to death. Like how mammals with double coats or winter coats like dogs or horses can have snow on top of their fur and the snow won't melt - because there's no heat escaping to melt it. Same with chickens. The surface of their feathers is cold. So they won't be giving the other chickens any of their body heat. The other chickens are there only for company and safety (safety in numbers), not for heat. Young chicks that still have down instead of feathers (and as their feathers are growing in) do huddle for warmth, because down isn't as good at insulation and they can get chilled. Note how young chicks have to actually stuff themselves inside the feathers of the mother, up against her skin, to receive any warmth. They don't huddle next to her. And also note how a broody hen plucks her breast to expose skin, so she can keep the eggs warm through direct contact with her body, not the feathers. And when she sits on the eggs, they get enveloped by the down on her underside and sink deep in, until they reach skin between the feathers, to receive heat. Chickens with defective feathers that aren't doing a good job of insulating (like silkies), chickens with naked areas like turkens or molting chickens, which are losing body heat, can huddle for warmth. But healthy normal chickens that have intact plumage don't warm each other up.
Your broody will be fine in a crate for a few days, if the crate is in a sheltered location that doesn't get wet or windy. Break her because this is really not a good time to be broody at all.
