It is fine, so long as you have a warm place for the babies.  You'll need something inside a building.  It'll need to be a warm building to help avoid the risk of cold drafts on the chicks. Basements, heated outbuildings, heated garages, etc. are common. If you just have a few birds and no indoor cats/dogs/rampaging young children, then you could keep them in the main part of the house, even, for a few days.  A lot of people use a second bathroom and take care of chicks right in the bathtub.  (Take the precaution of turning off the tub & shower water source, especially if you have children...)
When they are ready to move to their more grown up quarters then you will have to figure a way out to transition them so that they can adjust to colder temperatures. You don't want to take them from a 70 degree house straight to a 30 degree garage or a 10 degree coop.  Even with a heat lamp or two this is just too much stress!